diff --git a/.ghci b/.ghci
deleted file mode 100644
--- a/.ghci
+++ /dev/null
@@ -1,1 +0,0 @@
-:set -isrc -idist/build/autogen -optP-include -optPdist/build/autogen/cabal_macros.h
diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 dist
+dist-newstyle
 docs
 wiki
 TAGS
@@ -11,3 +12,21 @@
 *.hi
 *~
 *#
+.stack-work/
+cabal-dev
+*.chi
+*.chs.h
+*.dyn_o
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+cabal.project.local
+cabal.project.local~
+.HTF/
+.ghc.environment.*
diff --git a/.hlint.yaml b/.hlint.yaml
new file mode 100644
--- /dev/null
+++ b/.hlint.yaml
@@ -0,0 +1,7 @@
+- arguments: [-XCPP]
+
+- ignore: {name: Use fmap}
+- ignore: {name: Avoid lambda}
+- ignore: {name: Redundant lambda}
+- ignore: {name: Unused LANGUAGE pragma}
+- ignore: {name: Eta reduce, within: [Linear.Plucker, Linear.Quaternion, Linear.V, Linear.V0, Linear.V1, Linear.V2, Linear.V3, Linear.V4]}
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
--- a/.travis.yml
+++ /dev/null
@@ -1,28 +0,0 @@
-language: haskell
-before_install:
-  # Uncomment whenever hackage is down.
-  # - mkdir -p ~/.cabal && cp travis/config ~/.cabal/config && cabal update
-
-  # Try installing some of the build-deps with apt-get for speed.
-  - travis/cabal-apt-install --only-dependencies --force-reinstall $mode
-
-  - sudo apt-get -q -y install hlint || cabal install hlint
-
-install:
-  - cabal configure $mode
-  - cabal build
-
-script:
-  - $script
-  - hlint src --cpp-define HLINT
-
-notifications:
-  irc:
-    channels:
-      - "irc.freenode.org#haskell-lens"
-    skip_join: true
-    template:
-      - "\x0313linear\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
-
-env:
-  - mode="--enable-tests" script="cabal test"
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,420 @@
+1.23.3 [2026.01.10]
+-------------------
+* Remove unused `ghc-prim`, `tagged, `transformers-compat`, and `void`
+  dependencies.
+
+1.23.2 [2025.06.17]
+-------------------
+* Replace `test-framework` with `tasty` in the test suite.
+
+1.23.1 [2025.03.03]
+-------------------
+* Add `Uniform` and `UniformRange` instances for `Plucker`, `Quaternion`, `V`,
+  and `V{0,1,2,3,4}`.
+
+1.23 [2024.04.15]
+-----------------
+* The direction of interpolation of `lerp` has been reversed;
+  now `lerp 0 a b == a` and `lerp 1 a b == b`.
+  This brings `lerp` in line not only with its implementation
+  in other languages and frameworks, but also with `slerp` in this package.
+
+1.22 [2022.11.30]
+-----------------
+* The types of `_Point` and `lensP` have been generalized:
+
+  ```diff
+  -_Point :: Iso' (Point f a) (f a)
+  +_Point :: Iso (Point f a) (Point g b) (f a) (g b)
+
+  -lensP :: Lens' (Point g a) (g a)
+  +lensP :: Lens (Point f a) (Point g b) (f a) (g b)
+  ```
+
+  There is a chance that existing uses of `_Point` or `lensP` will fail to
+  typecheck due to their more general types. You can use `_Point.simple` or
+  `lensP.simple` to restore their old, more restricted types (where `simple`
+  comes from `Control.Lens` in the `lens` library).
+
+1.21.10 [2022.06.21]
+--------------------
+* Allow building with `vector-0.13.*`.
+
+1.21.9 [2022.05.18]
+-------------------
+* Allow building with `transformers-0.6.*`.
+
+1.21.8 [2021.11.15]
+-------------------
+* Allow building with `hashable-1.4.*`.
+* Drop support for pre-8.0 versions of GHC.
+
+1.21.7 [2021.09.20]
+-------------------
+* Fix a build error when using `random-1.2.1` or later.
+
+1.21.6 [2021.07.05]
+-------------------
+* Fix a build error when configured with `-template-haskell`.
+
+1.21.5 [2021.02.18]
+-------------------
+* Allow building with `lens-5.*`.
+
+1.21.4 [2021.01.29]
+-------------------
+* Allow building with `vector-0.12.2` or later.
+* The build-type has been changed from `Custom` to `Simple`.
+  To achieve this, the `doctests` test suite has been removed in favor of using
+  [`cabal-docspec`](https://github.com/phadej/cabal-extras/tree/master/cabal-docspec)
+  to run the doctests.
+
+1.21.3 [2020.10.03]
+-------------------
+* Allow building with GHC 9.0.
+
+1.21.2 [2020.09.30]
+-------------------
+* Use `base-orphans-0.8.3` or later. This means that the `Linear.Instances`
+  module no longer defines any orphan instances of its own, and the module is
+  now a simple shim on top of `Data.Orphans` from `base-orphans`.
+
+1.21.1 [2020.06.25]
+-------------------
+* Allow building with `random-1.2.*`.
+
+1.21 [2020.02.03]
+-----------------
+* Add instances for direct sums (`Product`) and tensor products (`Compose`) of
+  other vector spaces. This makes is much more convenient to do things like treat
+  a matrix temporarily as a vector through Compose, or to consider things like
+  Gauss-Jordan elimination, which wants augmented structures.
+* Add `frobenius` for computing the Frobenius norm of a matrix.
+* Added `Random` instances for `System.Random`. We had an indirect dependency
+  through `vector` anyways.
+* Add "obvious" zipping `Semigroup` and `Monoid` instances to all the
+  representable vector spaces.
+* Add `R1`..`R4` instances to `Quaternion`. `_w` is the scalar component so that
+  `_x`,`_y`,`_z` can be directional.
+* Add more solvers to `Linear.Matrix`, available with `base-4.8` or later.
+* Add `unangle` function to `Linear.V2`.
+
+1.20.9 [2019.05.02]
+-------------------
+* Derive `Lift` instances for `Plucker`, `Quaternion`, and `V{0,1,2,3,4}`.
+
+1.20.8 [2018.07.03]
+-------------------
+* Add instances of the `Field` classes from `lens`.
+* Add `Epsilon` instance for `Complex`.
+* Use specialized implementations of the `null` and `length` methods in
+  `Foldable` instances.
+* Add `Hashable1` instances for data types in `linear`. Also add a
+  `Hashable` instance for `V`.
+* Fix a bug in which `Quaternion`s were incorrectly exponentiated.
+
+1.20.7
+------
+* Support `semigroupoids-5.2.1` and `doctest-0.12`
+
+1.20.6
+------
+* Revamp `Setup.hs` to use `cabal-doctest`. This makes it build
+  with `Cabal-2.0`, and makes the `doctest`s work with `cabal new-build` and
+  sandboxes.
+* Make `(1 / x)` and `recip x` agree in the `Fractional` instance for `Quaternion`
+* Use newtype instances for `Point` vectors in `Linear.Affine`
+* Enable `PolyKinds` in `Linear.Trace`. Also enable `PolyKinds` when GHC 7.6 or
+  later is used (previously, it was GHC 7.8 or later).
+* Fix a segfault arising from the `MVector` instance for `V`
+* Add `Finite` class for conversion between `V` and fixed-size vector types
+
+1.20.5
+------
+* GHC 8 compatibility
+* Fixed the `perspective` calculation.
+
+1.20.4
+------
+* Compatibility with `base-orphans` 0.5
+
+1.20.3
+------
+* Support `vector` 0.11.0.0.
+* Support `cereal` 0.5
+* You can now unboxed vectors of `V n` vectors.
+
+1.20.2
+------
+* Modified the `doctest` machinery to work with `stack` and builds to non-standard locations.
+* Removed the local `.ghci` file.
+* Various numerical stability improvements were made to the quaternion and projection functions.
+
+1.20.1
+------
+* Fixed doctests broken by the previous change.
+* Unboxed vector instances for various linear data types now use unpacked integers even on older GHCs.
+
+1.20
+----
+* `inv22`, `inv33` and `inv44` no longer attempt an epsilon check. They no longer return a `Maybe` result as a consequence.
+  You should filter for the 0 determinant case yourself.
+
+1.19.1.3
+--------
+* `vector` 0.11.0.0 support
+
+1.19.1.2
+--------
+* Fix GHC 7.4.
+
+1.19.1.1
+--------
+* Proper `reflection` 2 support
+
+1.19.1
+------
+* `reflection` 2 support
+
+1.19
+----
+* Change the Ixed instance for `Linear.V` to use `Int` as the index type. This makes `V n` a _lot_ easier to use.
+
+1.18.3
+------
+* Compile warning-free on GHC 7.10.
+
+
+1.18.2
+------
+* Added `NFData` instance for `Point`
+
+1.18.1
+------
+* Added an `-f-template-haskell` option to allow disabling `template-haskell` support. This is an unsupported configuration but may be useful for expert users in sandbox configurations.
+* Added lenses for extracting corner various sub-matrices e.g. `_m22`, `_m33`
+
+1.18.0.2
+--------
+* Fixed builds on even older GHCs.
+
+1.18.0.1
+--------
+* Fixed the test suite.
+* Fixed builds on older GHCs.
+
+1.18
+----
+* Consolidated `eye2` .. `eye4` into a single `identity` combinator.
+* Fixed the `Data` instance `V n a` for GHC 7.10-RC3.
+
+1.17.1.1
+--------
+* `filepath` 1.4 support
+
+1.17.1
+------
+* Added support for `Data.Functor.Classes` from `transformers` 0.5 via `transformers-compat`.
+* Added missing support for `binary`, `bytes` and `cereal` for `Point`
+
+1.17
+----
+* Better support for `binary`. Added support for `bytes` and `cereal`
+
+1.16.4
+------
+* `ortho` and `inverseOrtho` now only require a `Fractional` constraint.
+* Added missing `Floating` instances.
+
+1.16.3
+----
+* Improve the performance of `fromQuaternion`, `mkTransformation`,
+  `mkTransformationMat`, `basisFor`, `scaled` by using implementations
+  that inline well for functions that were previously reference
+  implementations.
+
+1.16.2
+----
+* Added `NFData` instances for the various vector types.
+* Added `!!/` operator for matrix division by scalar.
+
+1.16.1
+----
+* Added `Trace` instance for `V1`.
+
+1.16
+----
+* Renamed `kronecker` to `scaled`.
+
+1.15.5
+------
+* Added `Metric` instances for `[]`, `ZipList`, `Maybe`
+* Added `det44` and `inv44` to `Linear.Matrix`
+* Added `Data` instance for `Point`
+
+1.15.4
+------
+* Added Typeable and Data instances for V
+
+1.15.3
+------
+* Added missing `FunctorWithIndex`, `FoldableWithIndex` and `TraversableWithIndex Int (V n)` instances for `V`
+
+1.15.2
+------
+* Added `frustum`, analogous to the old `glFrustum` call.
+* Added `inverseInfinitePerspective`, `inverseOrtho`, `inverseFrustum`.
+
+1.15.1
+------
+* Added `inversePerspective`. It is much more accurate to compute it directly than to compute an inverse.
+
+1.15.0.1
+--------
+* Fixed build failures caused by `Linear` re-exporting the old name.
+
+1.15
+----
+* Renamed `Linear.Perspective` to `Linear.Projection`.
+* Fixed a build issue with GHC HEAD.
+
+1.14.0.1
+--------
+* Fixed test failures caused by 1.14
+
+1.14
+----
+* Moved `Coincides` to `Linear.Plucker.Coincides`. The constructors `Line` and `Ray` oft collided with user code.
+
+1.13
+----
+* Switched 'ortho' to follow the OpenGL handedness.
+
+1.12.1
+------
+* Added "swizzle" lenses **e.g.** `_yzx`, which are useful for working with libraries like `gl`.
+
+1.12
+------
+* Added 'transpose'
+* Added missing 'Mxy' matrices up to 4 dimensions -- they were commonly reimplemented by users.
+
+1.11.3
+------
+* Fixed an issue with `UndecidableInstances` on GHC 7.6.3
+
+1.11.2
+------
+* Added `Linear.Perspective`.
+
+1.11.1
+------
+* Added `_Point`, `relative` and a few instances for `Point`.
+
+1.11
+----
+* Changed the 'representation' of `V n` from `E (V n)`, which was hard to use, to `Int`, which is a bit too permissive, but is easy to use.
+
+1.10.1
+------
+* Added `Linear.V2.angle`.
+
+1.10
+----
+* Added `Hashable` instances.
+
+1.9.1
+-----
+* Added a role annotation to `V n a` to prevent users from using GHC 7.8's `Coercible` machinery to violate invariants.
+
+1.9.0.1
+-----
+* Fixed a broken build
+
+1.9
+---
+* Added `MonadZip` instances.
+* Added `MonadFix` instances.
+* Added `Control.Lens.Each.Each` instances
+
+1.8.1
+-----
+* Bugfixed `slerp`
+
+1.8
+---
+* Added missing `Unbox` instances for working with unboxed vectors of `linear` data types.
+
+1.7
+---
+* Fixed `axisAngle`
+* `unit` now has a rank 1 type.
+
+1.5
+---
+* `lens` 4 compatibility
+
+1.4
+---
+* Renamed `incore` to `column` and added an example.
+
+1.3.1.1
+-------
+* Build bugfix
+
+1.3.1
+---
+* Better implementations of `basis` and `basisFor`.
+* Derived Generic instances.
+
+1.2
+---
+* Improved matrix multiplication to properly support the sparse/sparse case.
+
+1.1.4
+-----
+* Marked modules `Trustworthy` as necessary.
+
+1.1.2
+-----
+* Dependency bump for `reflection` compatibility
+
+1.1.1
+-----
+* Fixed an infinite loop in the default definition of `liftI2`.
+
+1.1
+---
+* Added `Additive` instances for `[]`, `Maybe` and `Vector`.
+
+1.0
+---
+* Strict vectors
+* Exported `mkTransformationMat`
+* Bumped dependency bounds
+
+0.9.1 [bug fix]
+-----
+* Exported `Linear.V0`!
+
+0.9
+---
+* Added sparse vector support.
+
+0.8
+---
+* Added `Linear.V0`
+
+0.7
+---
+* Added `Linear.Instances`
+* More documentation
+
+0.6
+---
+* Removed the direct dependency on `lens`.
+* Added `Linear.Core` to cover vector spaces as corepresentable functors.
+
 0.5
 -------
 * Added `Ix` instances for `V2`, `V3`, and `V4`
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright 2011-13 Edward Kmett
+Copyright 2011-2015 Edward Kmett
 
 All rights reserved.
 
diff --git a/README.markdown b/README.markdown
--- a/README.markdown
+++ b/README.markdown
@@ -1,6 +1,8 @@
 linear
 ======
 
+[![Hackage](https://img.shields.io/hackage/v/linear.svg)](https://hackage.haskell.org/package/linear) [![Build Status](https://github.com/ekmett/linear/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/linear/actions?query=workflow%3AHaskell-CI)
+
 Highly polymorphic vector space operations on sparse and free vector spaces.
 
 Contact Information
diff --git a/Setup.lhs b/Setup.lhs
--- a/Setup.lhs
+++ b/Setup.lhs
@@ -1,44 +1,7 @@
 #!/usr/bin/runhaskell
-\begin{code}
-{-# OPTIONS_GHC -Wall #-}
-module Main (main) where
-
-import Data.List ( nub )
-import Data.Version ( showVersion )
-import Distribution.Package ( PackageName(PackageName), PackageId, InstalledPackageId, packageVersion, packageName )
-import Distribution.PackageDescription ( PackageDescription(), TestSuite(..) )
-import Distribution.Simple ( defaultMainWithHooks, UserHooks(..), simpleUserHooks )
-import Distribution.Simple.Utils ( rewriteFile, createDirectoryIfMissingVerbose )
-import Distribution.Simple.BuildPaths ( autogenModulesDir )
-import Distribution.Simple.Setup ( BuildFlags(buildVerbosity), fromFlag )
-import Distribution.Simple.LocalBuildInfo ( withLibLBI, withTestLBI, LocalBuildInfo(), ComponentLocalBuildInfo(componentPackageDeps) )
-import Distribution.Verbosity ( Verbosity )
-import System.FilePath ( (</>) )
-
-main :: IO ()
-main = defaultMainWithHooks simpleUserHooks
-  { buildHook = \pkg lbi hooks flags -> do
-     generateBuildModule (fromFlag (buildVerbosity flags)) pkg lbi
-     buildHook simpleUserHooks pkg lbi hooks flags
-  }
-
-generateBuildModule :: Verbosity -> PackageDescription -> LocalBuildInfo -> IO ()
-generateBuildModule verbosity pkg lbi = do
-  let dir = autogenModulesDir lbi
-  createDirectoryIfMissingVerbose verbosity True dir
-  withLibLBI pkg lbi $ \_ libcfg -> do
-    withTestLBI pkg lbi $ \suite suitecfg -> do
-      rewriteFile (dir </> "Build_" ++ testName suite ++ ".hs") $ unlines
-        [ "module Build_" ++ testName suite ++ " where"
-        , "deps :: [String]"
-        , "deps = " ++ (show $ formatdeps (testDeps libcfg suitecfg))
-        ]
-  where
-    formatdeps = map (formatone . snd)
-    formatone p = case packageName p of
-      PackageName n -> n ++ "-" ++ showVersion (packageVersion p)
+> module Main (main) where
 
-testDeps :: ComponentLocalBuildInfo -> ComponentLocalBuildInfo -> [(InstalledPackageId, PackageId)]
-testDeps xs ys = nub $ componentPackageDeps xs ++ componentPackageDeps ys
+> import Distribution.Simple
 
-\end{code}
+> main :: IO ()
+> main = defaultMain
diff --git a/linear.cabal b/linear.cabal
--- a/linear.cabal
+++ b/linear.cabal
@@ -1,75 +1,149 @@
 name:          linear
 category:      Math, Algebra
-version:       0.9.2
+version:       1.23.3
 license:       BSD3
-cabal-version: >= 1.8
+cabal-version: >= 1.10
 license-file:  LICENSE
 author:        Edward A. Kmett
 maintainer:    Edward A. Kmett <ekmett@gmail.com>
 stability:     provisional
 homepage:      http://github.com/ekmett/linear/
 bug-reports:   http://github.com/ekmett/linear/issues
-copyright:     Copyright (C) 2012-2013 Edward A. Kmett
+copyright:     Copyright (C) 2012-2015 Edward A. Kmett
 synopsis:      Linear Algebra
 description:   Types and combinators for linear algebra on free vector spaces
-build-type:    Custom
-tested-with:   GHC == 7.4.1, GHC == 7.4.2, GHC == 7.6.1
+build-type:    Simple
+tested-with:   GHC == 8.0.2
+             , GHC == 8.2.2
+             , GHC == 8.4.4
+             , GHC == 8.6.5
+             , GHC == 8.8.4
+             , GHC == 8.10.7
+             , GHC == 9.0.2
+             , GHC == 9.2.8
+             , GHC == 9.4.8
+             , GHC == 9.6.7
+             , GHC == 9.8.4
+             , GHC == 9.10.3
+             , GHC == 9.12.2
+             , GHC == 9.14.1
 extra-source-files:
-  .ghci
   .gitignore
-  .travis.yml
+  .hlint.yaml
   .vim.custom
-  travis/cabal-apt-install
-  travis/config
   CHANGELOG.markdown
   README.markdown
 
+flag template-haskell
+  description:
+    You can disable the use of the `template-haskell` package using `-f-template-haskell`.
+    .
+    Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
+  default: True
+  manual: True
+
+flag herbie
+  description: Enable `herbie`.
+  default: False
+  manual: True
+
 source-repository head
   type: git
-  location: git://github.com/ekmett/linear.git
+  location: https://github.com/ekmett/linear
 
 library
   build-depends:
-    base             >= 4.5 && < 5,
-    containers       >= 0.4 && < 0.6,
-    distributive     >= 0.2.2,
-    hashable         >= 1.1 && < 1.3,
-    semigroups       >= 0.9,
-    semigroupoids    >= 3,
-    transformers     >= 0.2 && < 0.4,
-    unordered-containers >= 0.2.3
+    adjunctions          >= 4     && < 5,
+    base                 >= 4.9   && < 5,
+    base-orphans         >= 0.8.3 && < 1,
+    binary               >= 0.5   && < 0.9,
+    bytes                >= 0.15  && < 1,
+    cereal               >= 0.4.1.1 && < 0.6,
+    containers           >= 0.4   && < 0.9,
+    deepseq              >= 1.1   && < 1.6,
+    distributive         >= 0.5.1 && < 1,
+    hashable             >= 1.2.7.0 && < 1.6,
+    indexed-traversable  >= 0.1.1 && < 0.2,
+    lens                 >= 4.15.2 && < 6,
+    random               >= 1.2   && < 1.4,
+    reflection           >= 2     && < 3,
+    semigroupoids        >= 5.2.1 && < 7,
+    transformers         >= 0.5   && < 0.7,
+    unordered-containers >= 0.2.3 && < 0.3,
+    vector               >= 0.12.1.2 && < 0.14
 
+  if flag(template-haskell) && impl(ghc)
+    build-depends: template-haskell >= 2.11.1.0 && < 3.0
+
+  if flag(herbie)
+    build-depends: HerbiePlugin >= 0.1 && < 0.2
+    ghc-options: -fplugin=Herbie
+    cpp-options: -DHERBIE
+
   exposed-modules:
     Linear
+    Linear.Affine
+    Linear.Algebra
+    Linear.Binary
     Linear.Conjugate
-    Linear.Core
+    Linear.Covector
     Linear.Epsilon
     Linear.Instances
     Linear.Matrix
     Linear.Metric
     Linear.Plucker
+    Linear.Plucker.Coincides
+    Linear.Projection
     Linear.Quaternion
+    Linear.Trace
+    Linear.V
     Linear.V0
+    Linear.V1
     Linear.V2
     Linear.V3
     Linear.V4
     Linear.Vector
 
-  ghc-options: -Wall -fwarn-tabs -O2 -fdicts-cheap -funbox-strict-fields
+  ghc-options: -Wall -Wtabs -O2 -fdicts-cheap -funbox-strict-fields -Wno-trustworthy-safe
   hs-source-dirs: src
 
--- Verify the results of the examples
+  default-language: Haskell2010
+
+  x-docspec-extra-packages: simple-reflect
+
+-- We need this dummy test-suite to add simple-reflect to the install plan
+--
+-- When cabal-install's extra-packages support becomes widely available
+-- (i.e. after 3.4 release), we can remove this test-suite.
 test-suite doctests
-  type:    exitcode-stdio-1.0
-  main-is: doctests.hs
-  build-depends:
-    base,
-    directory >= 1.0 && < 1.3,
-    doctest   >= 0.8 && < 0.10,
-    filepath  >= 1.3 && < 1.4,
-    lens      >= 3.7,
-    simple-reflect >= 0.3.1
+  type:              exitcode-stdio-1.0
+  main-is:           doctests.hs
+  hs-source-dirs:    tests
+  default-language:  Haskell2010
 
-  ghc-options: -Wall -Werror -threaded
+  build-depends: base < 5, simple-reflect >= 0.3.1
+
+test-suite test
+  type:           exitcode-stdio-1.0
+  main-is:        Test.hs
+  other-modules:  Prop.Quaternion
+                  Prop.V3
+                  Unit.Binary
+                  Unit.Plucker
+                  Unit.V
+  ghc-options:    -Wall -threaded
   hs-source-dirs: tests
+  build-depends:
+    base,
+    binary,
+    bytestring,
+    deepseq,
+    tasty >= 1.4 && < 1.6,
+    tasty-hunit >= 0.10 && < 0.11,
+    tasty-quickcheck >= 0.10 && < 0.12,
+    linear,
+    QuickCheck >= 2.5,
+    reflection,
+    vector
+  default-language: Haskell2010
 
diff --git a/src/Linear.hs b/src/Linear.hs
--- a/src/Linear.hs
+++ b/src/Linear.hs
@@ -1,7 +1,6 @@
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -12,32 +11,38 @@
 -- that make up the linear package.
 ----------------------------------------------------------------------------
 module Linear
-  ( module Linear.Conjugate
-  , module Linear.Core
+  ( module Linear.Algebra
+  , module Linear.Binary
+  , module Linear.Conjugate
+  , module Linear.Covector
   , module Linear.Epsilon
   , module Linear.Matrix
   , module Linear.Metric
-  , module Linear.Plucker
+  , module Linear.Projection
   , module Linear.Quaternion
+  , module Linear.Trace
   , module Linear.V0
+  , module Linear.V1
   , module Linear.V2
   , module Linear.V3
   , module Linear.V4
   , module Linear.Vector
   )  where
 
+import Linear.Algebra
+import Linear.Binary
 import Linear.Conjugate
-import Linear.Core
+import Linear.Covector
 import Linear.Epsilon
 import Linear.Instances ()
 import Linear.Matrix
 import Linear.Metric
-import Linear.Plucker
+import Linear.Projection
 import Linear.Quaternion
+import Linear.Trace
 import Linear.V0
+import Linear.V1
 import Linear.V2
 import Linear.V3
 import Linear.V4
 import Linear.Vector
-
-{-# ANN module "Hlint: ignore Use import/export shortcut" #-}
diff --git a/src/Linear/Affine.hs b/src/Linear/Affine.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Affine.hs
@@ -0,0 +1,303 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE DeriveTraversable #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- Operations on affine spaces.
+-----------------------------------------------------------------------------
+module Linear.Affine where
+
+import Control.Applicative
+import Control.DeepSeq
+import Control.Monad (liftM)
+import Control.Lens
+import Data.Binary as Binary
+import Data.Bytes.Serial
+import Data.Coerce
+import Data.Complex (Complex)
+import Data.Data
+import Data.Distributive
+import Data.Foldable as Foldable
+import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Product
+import Data.Functor.Rep as Rep
+import Data.HashMap.Lazy (HashMap)
+import Data.Hashable
+import Data.Hashable.Lifted
+import Data.IntMap (IntMap)
+import Data.Ix
+import Data.Kind
+import Data.Map (Map)
+#if !(MIN_VERSION_base(4,11,0))
+import Data.Semigroup (Semigroup)
+#endif
+import Data.Serialize as Cereal
+import Data.Vector (Vector)
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
+import Foreign.Storable
+import GHC.Generics (Generic, Generic1)
+import Linear.Epsilon
+import Linear.Metric
+import Linear.Plucker
+import Linear.Quaternion
+import Linear.V
+import Linear.V0
+import Linear.V1
+import Linear.V2
+import Linear.V3
+import Linear.V4
+import Linear.Vector
+import System.Random (Random(..))
+
+-- | An affine space is roughly a vector space in which we have
+-- forgotten or at least pretend to have forgotten the origin.
+--
+-- > a .+^ (b .-. a)  =  b@
+-- > (a .+^ u) .+^ v  =  a .+^ (u ^+^ v)@
+-- > (a .-. b) ^+^ v  =  (a .+^ v) .-. q@
+class Additive (Diff p) => Affine p where
+  type Diff p :: Type -> Type
+
+  infixl 6 .-.
+  -- | Get the difference between two points as a vector offset.
+  (.-.) :: Num a => p a -> p a -> Diff p a
+
+  infixl 6 .+^
+  -- | Add a vector offset to a point.
+  (.+^) :: Num a => p a -> Diff p a -> p a
+
+  infixl 6 .-^
+  -- | Subtract a vector offset from a point.
+  (.-^) :: Num a => p a -> Diff p a -> p a
+  p .-^ v = p .+^ negated v
+  {-# INLINE (.-^) #-}
+
+instance (Affine f, Affine g) => Affine (Product f g) where
+  type Diff (Product f g) = Product (Diff f) (Diff g)
+  Pair a b .-. Pair c d = Pair (a .-. c) (b .-. d)
+  Pair a b .+^ Pair c d = Pair (a .+^ c) (b .+^ d)
+  Pair a b .-^ Pair c d = Pair (a .+^ c) (b .+^ d)
+
+-- | Compute the quadrance of the difference (the square of the distance)
+qdA :: (Affine p, Foldable (Diff p), Num a) => p a -> p a -> a
+qdA a b = Foldable.sum (fmap (join (*)) (a .-. b))
+{-# INLINE qdA #-}
+
+-- | Distance between two points in an affine space
+distanceA :: (Floating a, Foldable (Diff p), Affine p) => p a -> p a -> a
+distanceA a b = sqrt (qdA a b)
+{-# INLINE distanceA #-}
+
+#define ADDITIVEC(CTX,T) instance CTX => Affine T where type Diff T = T ; \
+  (.-.) = (^-^) ; {-# INLINE (.-.) #-} ; (.+^) = (^+^) ; {-# INLINE (.+^) #-} ; \
+  (.-^) = (^-^) ; {-# INLINE (.-^) #-}
+#define ADDITIVE(T) ADDITIVEC((), T)
+
+ADDITIVE([])
+ADDITIVE(Complex)
+ADDITIVE(ZipList)
+ADDITIVE(Maybe)
+ADDITIVE(IntMap)
+ADDITIVE(Identity)
+ADDITIVE(Vector)
+ADDITIVE(V0)
+ADDITIVE(V1)
+ADDITIVE(V2)
+ADDITIVE(V3)
+ADDITIVE(V4)
+ADDITIVE(Plucker)
+ADDITIVE(Quaternion)
+ADDITIVE(((->) b))
+ADDITIVEC(Ord k, (Map k))
+ADDITIVEC((Eq k, Hashable k), (HashMap k))
+ADDITIVEC(Dim n, (V n))
+
+-- | A handy wrapper to help distinguish points from vectors at the
+-- type level
+newtype Point f a = P (f a)
+  deriving ( Eq, Ord, Show, Read, Monad, Functor, Applicative, Foldable
+           , Eq1, Ord1, Show1, Read1
+           , Traversable, Apply, Additive, Metric
+           , Fractional , Num, Ix, Storable, Epsilon
+           , Semigroup, Monoid
+           , Random, Hashable
+           , Generic, Generic1, Data
+           )
+
+instance Finite f => Finite (Point f) where
+  type Size (Point f) = Size f
+  toV (P v) = toV v
+  fromV v = P (fromV v)
+
+instance NFData (f a) => NFData (Point f a) where
+  rnf (P x) = rnf x
+
+instance Serial1 f => Serial1 (Point f) where
+  serializeWith f (P p) = serializeWith f p
+  deserializeWith m = P `liftM` deserializeWith m
+
+instance Serial (f a) => Serial (Point f a) where
+  serialize (P p) = serialize p
+  deserialize = P `liftM` deserialize
+
+instance Binary (f a) => Binary (Point f a) where
+  put (P p) = Binary.put p
+  get = P `liftM` Binary.get
+
+instance Serialize (f a) => Serialize (Point f a) where
+  put (P p) = Cereal.put p
+  get = P `liftM` Cereal.get
+
+instance Hashable1 f => Hashable1 (Point f) where
+  liftHashWithSalt h s (P f) = liftHashWithSalt h s f
+  {-# INLINE liftHashWithSalt #-}
+
+lensP :: Lens (Point f a) (Point g b) (f a) (g b)
+lensP afb (P a) = P <$> afb a
+{-# INLINE lensP #-}
+
+_Point :: Iso (Point f a) (Point g b) (f a) (g b)
+_Point = iso (\(P a) -> a) P
+{-# INLINE _Point #-}
+
+instance (t ~ Point g b) => Rewrapped (Point f a) t
+instance Wrapped (Point f a) where
+  type Unwrapped (Point f a) = f a
+  _Wrapped' = _Point
+  {-# INLINE _Wrapped' #-}
+
+-- These are stolen from Data.Profunctor.Unsafe
+(.#) :: Coercible b a => (b -> c) -> (a -> b) -> a -> c
+f .# _ = coerce f
+{-# INLINE (.#) #-}
+
+(#.) :: Coercible c b => (b -> c) -> (a -> b) -> a -> c
+(#.) _ = coerce (\x -> x :: b) :: forall a b. Coercible b a => a -> b
+{-# INLINE (#.) #-}
+
+unP :: Point f a -> f a
+unP (P x) = x
+{-# INLINE unP #-}
+
+-- We can't use GND to derive 'Bind' because 'join' causes
+-- role troubles. However, GHC 7.8 and above let us use
+-- explicit coercions for (>>-).
+instance Bind f => Bind (Point f) where
+  (>>-) = ((P .) . (. (unP .))) #. (>>-) .# unP
+  join (P m) = P $ m >>- \(P m') -> m'
+
+instance Distributive f => Distributive (Point f) where
+  distribute = P . collect (\(P p) -> p)
+  collect = (P .) #. collect .# (unP .)
+
+instance Representable f => Representable (Point f) where
+  type Rep (Point f) = Rep f
+  tabulate = P #. tabulate
+  {-# INLINE tabulate #-}
+  index = Rep.index .# unP
+  {-# INLINE index #-}
+
+type instance Index (Point f a) = Index (f a)
+type instance IxValue (Point f a) = IxValue (f a)
+
+instance Ixed (f a) => Ixed (Point f a) where
+  ix l = lensP . ix l
+  {-# INLINE ix #-}
+
+instance Traversable f => Each (Point f a) (Point f b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+instance R1 f => R1 (Point f) where
+  _x = lensP . _x
+  {-# INLINE _x #-}
+
+instance R2 f => R2 (Point f) where
+  _y = lensP . _y
+  {-# INLINE _y #-}
+  _xy = lensP . _xy
+  {-# INLINE _xy #-}
+
+instance R3 f => R3 (Point f) where
+  _z = lensP . _z
+  {-# INLINE _z #-}
+  _xyz = lensP . _xyz
+  {-# INLINE _xyz #-}
+
+instance R4 f => R4 (Point f) where
+  _w = lensP . _w
+  {-# INLINE _w #-}
+  _xyzw = lensP . _xyzw
+  {-# INLINE _xyzw #-}
+
+instance Additive f => Affine (Point f) where
+  type Diff (Point f) = f
+  (.-.) = (. unP) #. (^-^) .# unP
+  {-# INLINE (.-.) #-}
+  (.+^) = (P .) #. (^+^) .# unP
+  {-# INLINE (.+^) #-}
+  (.-^) = (P .) #. (^-^) .# unP
+  {-# INLINE (.-^) #-}
+
+-- | Vector spaces have origins.
+origin :: (Additive f, Num a) => Point f a
+origin = P zero
+
+-- | An isomorphism between points and vectors, given a reference
+--   point.
+relative :: (Additive f, Num a) => Point f a -> Iso' (Point f a) (f a)
+relative p0 = iso (.-. p0) (p0 .+^)
+{-# INLINE relative #-}
+
+newtype instance U.Vector    (Point f a) =  V_P (U.Vector    (f a))
+newtype instance U.MVector s (Point f a) = MV_P (U.MVector s (f a))
+instance U.Unbox (f a) => U.Unbox (Point f a)
+
+instance U.Unbox (f a) => M.MVector U.MVector (Point f a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_P v) = M.basicLength v
+  basicUnsafeSlice m n (MV_P v) = MV_P (M.basicUnsafeSlice m n v)
+  basicOverlaps (MV_P v) (MV_P u) = M.basicOverlaps v u
+  basicUnsafeNew n = MV_P `liftM` M.basicUnsafeNew n
+  basicUnsafeRead (MV_P v) i = P `liftM` M.basicUnsafeRead v i
+  basicUnsafeWrite (MV_P v) i (P x) = M.basicUnsafeWrite v i x
+  basicInitialize (MV_P v) = M.basicInitialize v
+  {-# INLINE basicInitialize #-}
+
+instance U.Unbox (f a) => G.Vector U.Vector (Point f a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_P v) = V_P `liftM` G.basicUnsafeFreeze v
+  basicUnsafeThaw   ( V_P v) = MV_P `liftM` G.basicUnsafeThaw   v
+  basicLength       ( V_P v) = G.basicLength v
+  basicUnsafeSlice m n (V_P v) = V_P (G.basicUnsafeSlice m n v)
+  basicUnsafeIndexM (V_P v) i = P `liftM` G.basicUnsafeIndexM v i
diff --git a/src/Linear/Algebra.hs b/src/Linear/Algebra.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Algebra.hs
@@ -0,0 +1,136 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+-----------------------------------------------------------------------------
+-- |
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-----------------------------------------------------------------------------
+module Linear.Algebra
+  ( Algebra(..)
+  , Coalgebra(..)
+  , multRep, unitalRep
+  , comultRep, counitalRep
+  ) where
+
+import Control.Lens hiding (index)
+import Data.Functor.Rep
+import Data.Complex
+import Data.Void
+import Linear.Vector
+import Linear.Quaternion
+import Linear.Conjugate
+import Linear.V0
+import Linear.V1
+import Linear.V2
+import Linear.V3
+import Linear.V4
+
+-- | An associative unital algebra over a ring
+class Num r => Algebra r m where
+  mult :: (m -> m -> r) -> m -> r
+  unital :: r -> m -> r
+
+multRep :: (Representable f, Algebra r (Rep f)) => f (f r) -> f r
+multRep ffr = tabulate $ mult (index . index ffr)
+
+unitalRep :: (Representable f, Algebra r (Rep f)) => r -> f r
+unitalRep = tabulate . unital
+
+instance Num r => Algebra r Void where
+  mult _ _ = 0
+  unital _ _ = 0
+
+instance Num r => Algebra r (E V0) where
+  mult _ _ = 0
+  unital _ _ = 0
+
+instance Num r => Algebra r (E V1) where
+  mult f _ = f ex ex
+  unital r _ = r
+
+instance Num r => Algebra r () where
+  mult f () = f () ()
+  unital r () = r
+
+instance (Algebra r a, Algebra r b) => Algebra r (a, b) where
+  mult f (a,b) = mult (\a1 a2 -> mult (\b1 b2 -> f (a1,b1) (a2,b2)) b) a
+  unital r (a,b) = unital r a * unital r b
+
+instance Num r => Algebra r (E Complex) where
+  mult f = \ i -> c^.el i where
+   c = (f ee ee - f ei ei) :+ (f ee ei + f ei ee)
+  unital r i = (r :+ 0)^.el i
+
+instance (Num r, TrivialConjugate r) => Algebra r (E Quaternion) where
+  mult f = index $ Quaternion
+    (f ee ee - (f ei ei + f ej ej + f ek ek))
+    (V3 (f ee ei + f ei ee + f ej ek - f ek ej)
+        (f ee ej + f ej ee + f ek ei - f ei ek)
+        (f ee ek + f ek ee + f ei ej - f ej ei))
+  unital r = index (Quaternion r 0)
+
+-- | A coassociative counital coalgebra over a ring
+class Num r => Coalgebra r m where
+  comult :: (m -> r) -> m -> m -> r
+  counital :: (m -> r) -> r
+
+comultRep :: (Representable f, Coalgebra r (Rep f)) => f r -> f (f r)
+comultRep fr = tabulate $ \i -> tabulate $ \j -> comult (index fr) i j
+
+counitalRep :: (Representable f, Coalgebra r (Rep f)) => f r -> r
+counitalRep = counital . index
+
+instance Num r => Coalgebra r Void where
+  comult _ _ _ = 0
+  counital _ = 0
+
+instance Num r => Coalgebra r () where
+  comult f () () = f ()
+  counital f = f ()
+
+instance Num r => Coalgebra r (E V0) where
+  comult _ _ _ = 0
+  counital _ = 0
+
+instance Num r => Coalgebra r (E V1) where
+  comult f _ _ = f ex
+  counital f = f ex
+
+instance Num r => Coalgebra r (E V2) where
+  comult f = index . index v where
+    v = V2 (V2 (f ex) 0) (V2 0 (f ey))
+  counital f = f ex + f ey
+
+instance Num r => Coalgebra r (E V3) where
+  comult f = index . index q where
+    q = V3 (V3 (f ex) 0 0)
+           (V3 0 (f ey) 0)
+           (V3 0 0 (f ez))
+  counital f = f ex + f ey + f ez
+
+instance Num r => Coalgebra r (E V4) where
+  comult f = index . index v where
+    v = V4 (V4 (f ex) 0 0 0) (V4 0 (f ey) 0 0) (V4 0 0 (f ez) 0) (V4 0 0 0 (f ew))
+  counital f = f ex + f ey + f ez + f ew
+
+instance Num r => Coalgebra r (E Complex) where
+  comult f = \i j -> c^.el i.el j where
+    c = (f ee :+ 0) :+ (0 :+ f ei)
+  counital f = f ee + f ei
+
+instance (Num r, TrivialConjugate r) => Coalgebra r (E Quaternion) where
+  comult f = index . index
+    (Quaternion (Quaternion (f ee) (V3 0 0 0))
+            (V3 (Quaternion 0 (V3 (f ei) 0 0))
+                (Quaternion 0 (V3 0 (f ej) 0))
+                (Quaternion 0 (V3 0 0 (f ek)))))
+  counital f = f ee + f ei + f ej + f ek
+
+instance (Coalgebra r m, Coalgebra r n) => Coalgebra r (m, n) where
+  comult f (a1, b1) (a2, b2) = comult (\a -> comult (\b -> f (a, b)) b1 b2) a1 a2
+  counital k = counital $ \a -> counital $ \b -> k (a,b)
diff --git a/src/Linear/Binary.hs b/src/Linear/Binary.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Binary.hs
@@ -0,0 +1,27 @@
+-----------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2013-2015 Edward Kmett and Anthony Cowley
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- Serialization of statically-sized types with the "Data.Binary"
+-- library.
+------------------------------------------------------------------------------
+module Linear.Binary
+  ( putLinear
+  , getLinear
+  ) where
+
+import Data.Binary
+import Data.Foldable (traverse_)
+
+-- | Serialize a linear type.
+putLinear :: (Binary a, Foldable t) => t a -> Put
+putLinear = traverse_ put
+
+-- | Deserialize a linear type.
+getLinear :: (Binary a, Applicative t, Traversable t) => Get (t a)
+getLinear = sequenceA $ pure get
diff --git a/src/Linear/Conjugate.hs b/src/Linear/Conjugate.hs
--- a/src/Linear/Conjugate.hs
+++ b/src/Linear/Conjugate.hs
@@ -1,7 +1,9 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DefaultSignatures #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Conjugate
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -12,12 +14,18 @@
 ----------------------------------------------------------------------------
 module Linear.Conjugate
   ( Conjugate(..)
+  , TrivialConjugate
   ) where
 
 import Data.Complex hiding (conjugate)
 import Data.Int
 import Data.Word
+import Foreign.C.Types (CFloat, CDouble)
 
+-- $setup
+-- >>> import Data.Complex (Complex (..))
+
+
 -- | An involutive ring
 class Num a => Conjugate a where
   -- | Conjugate a value. This defaults to the trivial involution.
@@ -28,8 +36,18 @@
   -- >>> conjugate 1
   -- 1
   conjugate :: a -> a
+#ifndef HLINT
+  default conjugate :: TrivialConjugate a => a -> a
   conjugate = id
+#endif
 
+-- | Requires and provides a default definition such that
+--
+-- @
+-- 'conjugate' = 'id'
+-- @
+class Conjugate a => TrivialConjugate a
+
 instance Conjugate Integer
 instance Conjugate Int
 instance Conjugate Int64
@@ -43,7 +61,26 @@
 instance Conjugate Word8
 instance Conjugate Double
 instance Conjugate Float
+instance Conjugate CFloat
+instance Conjugate CDouble
+
 instance (Conjugate a, RealFloat a) => Conjugate (Complex a) where
   {-# SPECIALIZE instance Conjugate (Complex Float) #-}
   {-# SPECIALIZE instance Conjugate (Complex Double) #-}
   conjugate (a :+ b) = conjugate a :+ negate b
+
+instance TrivialConjugate Integer
+instance TrivialConjugate Int
+instance TrivialConjugate Int64
+instance TrivialConjugate Int32
+instance TrivialConjugate Int16
+instance TrivialConjugate Int8
+instance TrivialConjugate Word
+instance TrivialConjugate Word64
+instance TrivialConjugate Word32
+instance TrivialConjugate Word16
+instance TrivialConjugate Word8
+instance TrivialConjugate Double
+instance TrivialConjugate Float
+instance TrivialConjugate CFloat
+instance TrivialConjugate CDouble
diff --git a/src/Linear/Core.hs b/src/Linear/Core.hs
deleted file mode 100644
--- a/src/Linear/Core.hs
+++ /dev/null
@@ -1,25 +0,0 @@
-{-# LANGUAGE RankNTypes #-}
------------------------------------------------------------------------------
--- |
--- Module      :  Linear.Core
--- Copyright   :  (C) 2012-2013 Edward Kmett,
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  experimental
--- Portability :  non-portable
---
--- Corepresentable functors as vector spaces
-----------------------------------------------------------------------------
-module Linear.Core
-  ( Core(..)
-  ) where
-
--- |
--- A 'Functor' @f@ is corepresentable if it is isomorphic to @(x -> a)@
--- for some x. Nearly all such functors can be represented by choosing @x@ to be
--- the set of lenses that are polymorphic in the contents of the 'Functor',
--- that is to say @x = 'Rep' f@ is a valid choice of 'x' for (nearly) every
--- 'Representable' 'Functor'.
-class Functor f => Core f where
-  core :: ((forall g x. Functor g => (x -> g x) -> f x -> g (f x)) -> a) -> f a
diff --git a/src/Linear/Covector.hs b/src/Linear/Covector.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Covector.hs
@@ -0,0 +1,73 @@
+{-# LANGUAGE CPP, MultiParamTypeClasses, FlexibleInstances, FlexibleContexts #-}
+-----------------------------------------------------------------------------
+-- |
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- Operations on affine spaces.
+-----------------------------------------------------------------------------
+module Linear.Covector
+  ( Covector(..)
+  , ($*)
+  ) where
+
+import Control.Applicative
+import Control.Monad
+import Data.Functor.Plus hiding (zero)
+import qualified Data.Functor.Plus as Plus
+import Data.Functor.Bind
+import Data.Functor.Rep as Rep
+import Linear.Algebra
+
+-- | Linear functionals from elements of an (infinite) free module to a scalar
+
+newtype Covector r a = Covector { runCovector :: (a -> r) -> r }
+
+infixr 0 $*
+
+($*) :: Representable f => Covector r (Rep f) -> f r -> r
+Covector f $* m = f (Rep.index m)
+
+instance Functor (Covector r) where
+  fmap f (Covector m) = Covector $ \k -> m (k . f)
+
+instance Apply (Covector r) where
+  Covector mf <.> Covector ma = Covector $ \k -> mf $ \f -> ma (k . f)
+
+instance Applicative (Covector r) where
+  pure a = Covector $ \k -> k a
+  Covector mf <*> Covector ma = Covector $ \k -> mf $ \f -> ma $ k . f
+
+instance Bind (Covector r) where
+  Covector m >>- f = Covector $ \k -> m $ \a -> runCovector (f a) k
+
+instance Monad (Covector r) where
+#if !(MIN_VERSION_base(4,11,0))
+  return a = Covector $ \k -> k a
+#endif
+  Covector m >>= f = Covector $ \k -> m $ \a -> runCovector (f a) k
+
+instance Num r => Alt (Covector r) where
+  Covector m <!> Covector n = Covector $ \k -> m k + n k
+
+instance Num r => Plus (Covector r) where
+  zero = Covector (const 0)
+
+instance Num r => Alternative (Covector r) where
+  Covector m <|> Covector n = Covector $ \k -> m k + n k
+  empty = Covector (const 0)
+
+instance Num r => MonadPlus (Covector r) where
+  Covector m `mplus` Covector n = Covector $ \k -> m k + n k
+  mzero = Covector (const 0)
+
+instance Coalgebra r m => Num (Covector r m) where
+  Covector f + Covector g = Covector $ \k -> f k + g k
+  Covector f - Covector g = Covector $ \k -> f k - g k
+  Covector f * Covector g = Covector $ \k -> f $ \m -> g $ comult k m
+  negate (Covector f) = Covector $ \k -> negate (f k)
+  abs _    = error "Covector.abs: undefined"
+  signum _ = error "Covector.signum: undefined"
+  fromInteger n = Covector $ \ k -> fromInteger n * counital k
diff --git a/src/Linear/Epsilon.hs b/src/Linear/Epsilon.hs
--- a/src/Linear/Epsilon.hs
+++ b/src/Linear/Epsilon.hs
@@ -1,7 +1,6 @@
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Epsilon
--- Copyright   :  (C) 2012 Edward Kmett
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
 -- Stability   :  provisional
@@ -12,6 +11,8 @@
 module Linear.Epsilon
   ( Epsilon(..)
   ) where
+import Data.Complex (Complex, magnitude)
+import Foreign.C.Types (CFloat, CDouble)
 
 -- | Provides a fairly subjective test to see if a quantity is near zero.
 --
@@ -37,3 +38,14 @@
 -- | @'abs' a '<=' 1e-12@
 instance Epsilon Double where
   nearZero a = abs a <= 1e-12
+
+-- | @'abs' a '<=' 1e-6@
+instance Epsilon CFloat where
+  nearZero a = abs a <= 1e-6
+
+-- | @'abs' a '<=' 1e-12@
+instance Epsilon CDouble where
+  nearZero a = abs a <= 1e-12
+
+instance (Epsilon a, RealFloat a) => Epsilon (Complex a) where
+  nearZero = nearZero . magnitude
diff --git a/src/Linear/Instances.hs b/src/Linear/Instances.hs
--- a/src/Linear/Instances.hs
+++ b/src/Linear/Instances.hs
@@ -1,77 +1,14 @@
-{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# LANGUAGE Safe #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Instances
--- Copyright   :  (C) 2012 Edward Kmett
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
 -- Stability   :  provisional
 -- Portability :  portable
 --
--- Orphans
+-- Re-exports orphan instances for @Complex@ from the @base-orphans@ package.
 -----------------------------------------------------------------------------
 module Linear.Instances () where
 
-import Control.Applicative
-import Data.Complex
-import Data.Foldable
-import Data.Functor.Bind
-import Data.HashMap.Lazy as HashMap
-import Data.Hashable
-import Data.Semigroup
-import Data.Semigroup.Foldable
-import Data.Semigroup.Traversable
-import Data.Traversable
-
-instance (Hashable k, Eq k) => Apply (HashMap k) where
-  (<.>) = HashMap.intersectionWith id
-
-instance (Hashable k, Eq k) => Bind (HashMap k) where
-  -- this is needlessly painful
-  m >>- f = HashMap.fromList $ do
-    (k, a) <- HashMap.toList m
-    case HashMap.lookup k (f a) of
-      Just b -> [(k,b)]
-      Nothing -> []
-
-instance Functor Complex where
-  fmap f (a :+ b) = f a :+ f b
-  {-# INLINE fmap #-}
-
-instance Apply Complex where
-  (a :+ b) <.> (c :+ d) = a c :+ b d
-
-instance Applicative Complex where
-  pure a = a :+ a
-  (a :+ b) <*> (c :+ d) = a c :+ b d
-
-instance Bind Complex where
-  (a :+ b) >>- f = a' :+ b' where
-    a' :+ _  = f a
-    _  :+ b' = f b
-  {-# INLINE (>>-) #-}
-
-instance Monad Complex where
-  return a = a :+ a
-  {-# INLINE return #-}
-
-  (a :+ b) >>= f = a' :+ b' where
-    a' :+ _  = f a
-    _  :+ b' = f b
-  {-# INLINE (>>=) #-}
-
-instance Foldable Complex where
-  foldMap f (a :+ b) = f a `mappend` f b
-  {-# INLINE foldMap #-}
-
-instance Traversable Complex where
-  traverse f (a :+ b) = (:+) <$> f a <*> f b
-  {-# INLINE traverse #-}
-
-instance Foldable1 Complex where
-  foldMap1 f (a :+ b) = f a <> f b
-  {-# INLINE foldMap1 #-}
-
-instance Traversable1 Complex where
-  traverse1 f (a :+ b) = (:+) <$> f a <.> f b
-  {-# INLINE traverse1 #-}
+import Data.Orphans ()
diff --git a/src/Linear/Matrix.hs b/src/Linear/Matrix.hs
--- a/src/Linear/Matrix.hs
+++ b/src/Linear/Matrix.hs
@@ -1,7 +1,14 @@
------------------------------------------------------------------------------
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
+
+---------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Matrix
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -9,67 +16,128 @@
 -- Portability :  non-portable
 --
 -- Simple matrix operation for low-dimensional primitives.
-----------------------------------------------------------------------------
+---------------------------------------------------------------------------
 module Linear.Matrix
-  ( (!*!), (!*) , (*!), (!!*), (*!!)
+  ( (!*!), (!+!), (!-!), (!*), (*!), (!!*), (*!!), (!!/)
+  , column
   , adjoint
-  , M22, M33, M44, M43, m33_to_m44, m43_to_m44
-  , det22, det33, inv22, inv33
-  , eye3, eye4
-  , trace
+  , M22, M23, M24, M32, M33, M34, M42, M43, M44
+  , m33_to_m44, m43_to_m44
+  , det22, det33, det44, inv22, inv33, inv44
+  , identity
+  , Trace(..)
   , translation
+  , transpose
   , fromQuaternion
   , mkTransformation
+  , mkTransformationMat
+  , _m22, _m23, _m24
+  , _m32, _m33, _m34
+  , _m42, _m43, _m44
+  , lu
+  , luFinite
+  , forwardSub
+  , forwardSubFinite
+  , backwardSub
+  , backwardSubFinite
+  , luSolve
+  , luSolveFinite
+  , luInv
+  , luInvFinite
+  , luDet
+  , luDetFinite
   ) where
 
-import Control.Applicative
-import Control.Monad (join)
+import Control.Lens hiding (index)
+import Control.Lens.Internal.Context
 import Data.Distributive
 import Data.Foldable as Foldable
-import Data.Functor.Apply
-import Linear.Epsilon
-import Linear.Metric
+import Data.Functor.Rep
+import GHC.TypeLits
 import Linear.Quaternion
+import Linear.V
 import Linear.V2
 import Linear.V3
 import Linear.V4
-import Linear.Vector ((*^))
+import Linear.Vector
 import Linear.Conjugate
+import Linear.Trace
 
 -- $setup
--- >>> import Data.Complex
--- >>> import Data.IntMap
+-- >>> import Control.Lens hiding (index)
+-- >>> import Data.Complex (Complex (..))
+-- >>> import Linear.V2
+-- >>> import Linear.V3
+-- >>> import Linear.V
+-- >>> import qualified Data.IntMap as IntMap
 -- >>> import Debug.SimpleReflect.Vars
 
+-- | This is a generalization of 'Control.Lens.inside' to work over any corepresentable 'Functor'.
+--
+-- @
+-- 'column' :: 'Representable' f => 'Lens' s t a b -> 'Lens' (f s) (f t) (f a) (f b)
+-- @
+--
+-- In practice it is used to access a column of a matrix.
+--
+-- >>> V2 (V3 1 2 3) (V3 4 5 6) ^._x
+-- V3 1 2 3
+--
+-- >>> V2 (V3 1 2 3) (V3 4 5 6) ^.column _x
+-- V2 1 4
+column :: Representable f => LensLike (Context a b) s t a b -> Lens (f s) (f t) (f a) (f b)
+column l f es = o <$> f i where
+   go = l (Context id)
+   i = tabulate $ \ e -> ipos $ go (index es e)
+   o eb = tabulate $ \ e -> ipeek (index eb e) (go (index es e))
+
 infixl 7 !*!
--- | Matrix product. This can compute mixed dense-dense, sparse-dense and sparse-sparse matrix products.
+-- | Matrix product. This can compute any combination of sparse and dense multiplication.
 --
 -- >>> V2 (V3 1 2 3) (V3 4 5 6) !*! V3 (V2 1 2) (V2 3 4) (V2 4 5)
 -- V2 (V2 19 25) (V2 43 58)
 --
--- >>> V2 (fromList [(1,2)]) (fromList [(2,3)]) !*! fromList [(1,V3 0 0 1), (2, V3 0 0 5)]
+-- >>> V2 (IntMap.fromList [(1,2)]) (IntMap.fromList [(2,3)]) !*! IntMap.fromList [(1,V3 0 0 1), (2, V3 0 0 5)]
 -- V2 (V3 0 0 2) (V3 0 0 15)
-(!*!) :: (Functor m, Foldable r, Apply r, Distributive n, Num a) => m (r a) -> r (n a) -> m (n a)
-f !*! g = fmap (\r -> Foldable.sum . liftF2 (*) r <$> g') f
-  where g' = distribute g
+(!*!) :: (Functor m, Foldable t, Additive t, Additive n, Num a) => m (t a) -> t (n a) -> m (n a)
+f !*! g = fmap (\ f' -> Foldable.foldl' (^+^) zero $ liftI2 (*^) f' g) f
 
+infixl 6 !+!
+-- | Entry-wise matrix addition.
+--
+-- >>> V2 (V3 1 2 3) (V3 4 5 6) !+! V2 (V3 7 8 9) (V3 1 2 3)
+-- V2 (V3 8 10 12) (V3 5 7 9)
+(!+!) :: (Additive m, Additive n, Num a) => m (n a) -> m (n a) -> m (n a)
+as !+! bs = liftU2 (^+^) as bs
+
+infixl 6 !-!
+-- | Entry-wise matrix subtraction.
+--
+-- >>> V2 (V3 1 2 3) (V3 4 5 6) !-! V2 (V3 7 8 9) (V3 1 2 3)
+-- V2 (V3 (-6) (-6) (-6)) (V3 3 3 3)
+(!-!) :: (Additive m, Additive n, Num a) => m (n a) -> m (n a) -> m (n a)
+as !-! bs = liftU2 (^-^) as bs
+
+infixl 7 !*
 -- | Matrix * column vector
 --
 -- >>> V2 (V3 1 2 3) (V3 4 5 6) !* V3 7 8 9
 -- V2 50 122
-infixl 7 *!
-(!*) :: (Functor m, Metric r, Num a) => m (r a) -> r a -> m a
-m !* v = dot v <$> m
-
-infixl 7 !*
+(!*) :: (Functor m, Foldable r, Additive r, Num a) => m (r a) -> r a -> m a
+m !* v = fmap (\r -> Foldable.sum $ liftI2 (*) r v) m
 
+infixl 7 *!
 -- | Row vector * matrix
 --
 -- >>> V2 1 2 *! V2 (V3 3 4 5) (V3 6 7 8)
 -- V3 15 18 21
-(*!) :: (Metric r, Distributive n, Num a) => r a -> r (n a) -> n a
-f *! g = dot f <$> distribute g
 
+-- (*!) :: (Metric r, Additive n, Num a) => r a -> r (n a) -> n a
+-- f *! g = dot f <$> distribute g
+
+(*!) :: (Num a, Foldable t, Additive f, Additive t) => t a -> t (f a) -> f a
+f *! g = sumV $ liftI2 (*^) f g
+
 infixl 7 *!!
 -- | Scalar-matrix product
 --
@@ -88,6 +156,12 @@
 (!!*) = flip (*!!)
 {-# INLINE (!!*) #-}
 
+infixl 7 !!/
+-- | Matrix-scalar division
+(!!/) :: (Functor m, Functor r, Fractional a) => m (r a) -> a -> m (r a)
+m !!/ s = fmap (^/ s) m
+{-# INLINE (!!/) #-}
+
 -- | Hermitian conjugate or conjugate transpose
 --
 -- >>> adjoint (V2 (V2 (1 :+ 2) (3 :+ 4)) (V2 (5 :+ 6) (7 :+ 8)))
@@ -96,46 +170,59 @@
 adjoint = collect (fmap conjugate)
 {-# INLINE adjoint #-}
 
--- | Compute the trace of a matrix
---
--- >>> trace (V2 (V2 a b) (V2 c d))
--- a + d
-trace :: (Monad f, Foldable f, Num a) => f (f a) -> a
-trace m = Foldable.sum (join m)
-{-# INLINE trace #-}
-
 -- * Matrices
 --
 -- Matrices use a row-major representation.
 
 -- | A 2x2 matrix with row-major representation
 type M22 a = V2 (V2 a)
+-- | A 2x3 matrix with row-major representation
+type M23 a = V2 (V3 a)
+-- | A 2x4 matrix with row-major representation
+type M24 a = V2 (V4 a)
+-- | A 3x2 matrix with row-major representation
+type M32 a = V3 (V2 a)
 -- | A 3x3 matrix with row-major representation
 type M33 a = V3 (V3 a)
--- | A 4x4 matrix with row-major representation
-type M44 a = V4 (V4 a)
+-- | A 3x4 matrix with row-major representation
+type M34 a = V3 (V4 a)
+-- | A 4x2 matrix with row-major representation
+type M42 a = V4 (V2 a)
 -- | A 4x3 matrix with row-major representation
 type M43 a = V4 (V3 a)
+-- | A 4x4 matrix with row-major representation
+type M44 a = V4 (V4 a)
 
 -- | Build a rotation matrix from a unit 'Quaternion'.
 fromQuaternion :: Num a => Quaternion a -> M33 a
 fromQuaternion (Quaternion w (V3 x y z)) =
-  V3 (V3 (1-2*(y2+z2)) (2*(x*y-z*w)) (2*(x*z+y*w)))
-     (V3 (2*(x*y+z*w)) (1-2*(x2+z2)) (2*(y*z-x*w)))
-     (V3 (2*(x*z-y*w)) (2*(y*z+x*w)) (1-2*(x2+y2)))
-  where x2 = x * x
-        y2 = y * y
-        z2 = z * z
+  V3 (V3 (1-2*(y2+z2)) (2*(xy-zw)) (2*(xz+yw)))
+     (V3 (2*(xy+zw)) (1-2*(x2+z2)) (2*(yz-xw)))
+     (V3 (2*(xz-yw)) (2*(yz+xw)) (1-2*(x2+y2)))
+  where x2 = x*x
+        y2 = y*y
+        z2 = z*z
+        xy = x*y
+        xz = x*z
+        xw = x*w
+        yz = y*z
+        yw = y*w
+        zw = z*w
+{-# INLINE fromQuaternion #-}
 
+-- | Build a transformation matrix from a rotation matrix and a
+-- translation vector.
 mkTransformationMat :: Num a => M33 a -> V3 a -> M44 a
 mkTransformationMat (V3 r1 r2 r3) (V3 tx ty tz) =
   V4 (snoc3 r1 tx) (snoc3 r2 ty) (snoc3 r3 tz) (V4 0 0 0 1)
   where snoc3 (V3 x y z) = V4 x y z
+{-# INLINE mkTransformationMat #-}
 
 -- |Build a transformation matrix from a rotation expressed as a
 -- 'Quaternion' and a translation vector.
 mkTransformation :: Num a => Quaternion a -> V3 a -> M44 a
 mkTransformation = mkTransformationMat . fromQuaternion
+{-# INLINE mkTransformation #-}
 
 -- | Convert from a 4x3 matrix to a 4x4 matrix, extending it with the @[ 0 0 0 1 ]@ column vector
 m43_to_m44 :: Num a => M43 a -> M44 a
@@ -148,39 +235,78 @@
      (V4 d e f 0)
      (V4 g h i 0)
      (V4 j k l 1)
-{-# ANN m43_to_m44 "HLint: ignore Use camelCase" #-}
 
 -- | Convert a 3x3 matrix to a 4x4 matrix extending it with 0's in the new row and column.
 m33_to_m44 :: Num a => M33 a -> M44 a
 m33_to_m44 (V3 r1 r2 r3) = V4 (vector r1) (vector r2) (vector r3) (point 0)
-{-# ANN m33_to_m44 "HLint: ignore Use camelCase" #-}
 
--- |3x3 identity matrix.
+-- |The identity matrix for any dimension vector.
 --
--- >>> eye3
+-- >>> identity :: M44 Int
+-- V4 (V4 1 0 0 0) (V4 0 1 0 0) (V4 0 0 1 0) (V4 0 0 0 1)
+-- >>> identity :: V3 (V3 Int)
 -- V3 (V3 1 0 0) (V3 0 1 0) (V3 0 0 1)
-eye3 :: Num a => M33 a
-eye3 = V3 (V3 1 0 0)
-          (V3 0 1 0)
-          (V3 0 0 1)
+identity :: (Num a, Traversable t, Applicative t) => t (t a)
+identity = scaled (pure 1)
 
--- |4x4 identity matrix.
---
--- >>> eye4
--- V4 (V4 1 0 0 0) (V4 0 1 0 0) (V4 0 0 1 0) (V4 0 0 0 1)
-eye4 :: Num a => M44 a
-eye4 = V4 (V4 1 0 0 0)
-          (V4 0 1 0 0)
-          (V4 0 0 1 0)
-          (V4 0 0 0 1)
+-- |Extract the translation vector (first three entries of the last
+-- column) from a 3x4 or 4x4 matrix.
+translation :: (Representable t, R3 t, R4 v) => Lens' (t (v a)) (V3 a)
+translation = column _w._xyz
+{-
+translation f rs = aux <$> f (view _w <$> view _xyz rs)
+ where aux (V3 x y z) = (_x._w .~ x) . (_y._w .~ y) . (_z._w .~ z) $ rs
 
+-- translation :: (R3 t, R4 v, Functor f, Functor t) => (V3 a -> f (V3 a)) -> t (v a) -> f (t a)
+-- translation = (. fmap (^._w)) . _xyz where
+--   x ^. l = getConst (l Const x)
+-}
 
--- |Extract the translation vector (first three entries of the last
--- column) from a 3x4 or 4x4 matrix
-translation :: (R3 t, R4 v, Functor f, Functor t) => (V3 a -> f (V3 a)) -> t (v a) -> f (t a)
-translation = (. fmap (^._w)) . _xyz where
-  x ^. l = getConst (l Const x)
+-- |Extract a 2x2 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m22 :: (Representable t, R2 t, R2 v) => Lens' (t (v a)) (M22 a)
+_m22 = column _xy._xy
 
+-- |Extract a 2x3 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m23 :: (Representable t, R2 t, R3 v) => Lens' (t (v a)) (M23 a)
+_m23 = column _xyz._xy
+
+-- |Extract a 2x4 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m24 :: (Representable t, R2 t, R4 v) => Lens' (t (v a)) (M24 a)
+_m24 = column _xyzw._xy
+
+-- |Extract a 3x2 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m32 :: (Representable t, R3 t, R2 v) => Lens' (t (v a)) (M32 a)
+_m32 = column _xy._xyz
+
+-- |Extract a 3x3 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m33 :: (Representable t, R3 t, R3 v) => Lens' (t (v a)) (M33 a)
+_m33 = column _xyz._xyz
+
+-- |Extract a 3x4 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m34 :: (Representable t, R3 t, R4 v) => Lens' (t (v a)) (M34 a)
+_m34 = column _xyzw._xyz
+
+-- |Extract a 4x2 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m42 :: (Representable t, R4 t, R2 v) => Lens' (t (v a)) (M42 a)
+_m42 = column _xy._xyzw
+
+-- |Extract a 4x3 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m43 :: (Representable t, R4 t, R3 v) => Lens' (t (v a)) (M43 a)
+_m43 = column _xyz._xyzw
+
+-- |Extract a 4x4 matrix from a matrix of higher dimensions by dropping excess
+-- rows and columns.
+_m44 :: (Representable t, R4 t, R4 v) => Lens' (t (v a)) (M44 a)
+_m44 = column _xyzw._xyzw
+
 -- |2x2 matrix determinant.
 --
 -- >>> det22 (V2 (V2 a b) (V2 c d))
@@ -199,29 +325,49 @@
           (V3 g h i)) = a * (e*i-f*h) - d * (b*i-c*h) + g * (b*f-c*e)
 {-# INLINE det33 #-}
 
+-- |4x4 matrix determinant.
+det44 :: Num a => M44 a -> a
+det44 (V4 (V4 i00 i01 i02 i03)
+          (V4 i10 i11 i12 i13)
+          (V4 i20 i21 i22 i23)
+          (V4 i30 i31 i32 i33)) =
+  let
+    s0 = i00 * i11 - i10 * i01
+    s1 = i00 * i12 - i10 * i02
+    s2 = i00 * i13 - i10 * i03
+    s3 = i01 * i12 - i11 * i02
+    s4 = i01 * i13 - i11 * i03
+    s5 = i02 * i13 - i12 * i03
+
+    c5 = i22 * i33 - i32 * i23
+    c4 = i21 * i33 - i31 * i23
+    c3 = i21 * i32 - i31 * i22
+    c2 = i20 * i33 - i30 * i23
+    c1 = i20 * i32 - i30 * i22
+    c0 = i20 * i31 - i30 * i21
+  in s0 * c5 - s1 * c4 + s2 * c3 + s3 * c2 - s4 * c1 + s5 * c0
+{-# INLINE det44 #-}
+
 -- |2x2 matrix inverse.
 --
 -- >>> inv22 $ V2 (V2 1 2) (V2 3 4)
--- Just (V2 (V2 (-2.0) 1.0) (V2 1.5 (-0.5)))
-inv22 :: (Epsilon a, Floating a) => M22 a -> Maybe (M22 a)
-inv22 m@(V2 (V2 a b) (V2 c d))
-  | nearZero det = Nothing
-  | otherwise = Just $ (1 / det) *!! V2 (V2 d (-b)) (V2 (-c) a)
+-- V2 (V2 (-2.0) 1.0) (V2 1.5 (-0.5))
+inv22 :: Fractional a => M22 a -> M22 a
+inv22 m@(V2 (V2 a b) (V2 c d)) = (1 / det) *!! V2 (V2 d (-b)) (V2 (-c) a)
   where det = det22 m
 {-# INLINE inv22 #-}
 
 -- |3x3 matrix inverse.
 --
 -- >>> inv33 $ V3 (V3 1 2 4) (V3 4 2 2) (V3 1 1 1)
--- Just (V3 (V3 0.0 0.5 (-1.0)) (V3 (-0.5) (-0.75) 3.5) (V3 0.5 0.25 (-1.5)))
-inv33 :: (Epsilon a, Floating a) => M33 a -> Maybe (M33 a)
+-- V3 (V3 0.0 0.5 (-1.0)) (V3 (-0.5) (-0.75) 3.5) (V3 0.5 0.25 (-1.5))
+inv33 :: Fractional a => M33 a -> M33 a
 inv33 m@(V3 (V3 a b c)
             (V3 d e f)
             (V3 g h i))
-  | nearZero det = Nothing
-  | otherwise = Just $ (1 / det) *!! V3 (V3 a' b' c')
-                                        (V3 d' e' f')
-                                        (V3 g' h' i')
+  = (1 / det) *!! V3 (V3 a' b' c')
+                     (V3 d' e' f')
+                     (V3 g' h' i')
   where a' = cofactor (e,f,h,i)
         b' = cofactor (c,b,i,h)
         c' = cofactor (b,c,e,f)
@@ -234,3 +380,352 @@
         cofactor (q,r,s,t) = det22 (V2 (V2 q r) (V2 s t))
         det = det33 m
 {-# INLINE inv33 #-}
+
+
+-- | 'transpose' is just an alias for 'distribute'
+--
+-- > transpose (V3 (V2 1 2) (V2 3 4) (V2 5 6))
+-- V2 (V3 1 3 5) (V3 2 4 6)
+transpose :: (Distributive g, Functor f) => f (g a) -> g (f a)
+transpose = distribute
+{-# INLINE transpose #-}
+
+-- |4x4 matrix inverse.
+inv44 :: Fractional a => M44 a -> M44 a
+inv44 (V4 (V4 i00 i01 i02 i03)
+          (V4 i10 i11 i12 i13)
+          (V4 i20 i21 i22 i23)
+          (V4 i30 i31 i32 i33)) =
+  let s0 = i00 * i11 - i10 * i01
+      s1 = i00 * i12 - i10 * i02
+      s2 = i00 * i13 - i10 * i03
+      s3 = i01 * i12 - i11 * i02
+      s4 = i01 * i13 - i11 * i03
+      s5 = i02 * i13 - i12 * i03
+      c5 = i22 * i33 - i32 * i23
+      c4 = i21 * i33 - i31 * i23
+      c3 = i21 * i32 - i31 * i22
+      c2 = i20 * i33 - i30 * i23
+      c1 = i20 * i32 - i30 * i22
+      c0 = i20 * i31 - i30 * i21
+      det = s0 * c5 - s1 * c4 + s2 * c3 + s3 * c2 - s4 * c1 + s5 * c0
+      invDet = recip det
+  in invDet *!! V4 (V4 (i11 * c5 - i12 * c4 + i13 * c3)
+                       (-i01 * c5 + i02 * c4 - i03 * c3)
+                       (i31 * s5 - i32 * s4 + i33 * s3)
+                       (-i21 * s5 + i22 * s4 - i23 * s3))
+                   (V4 (-i10 * c5 + i12 * c2 - i13 * c1)
+                       (i00 * c5 - i02 * c2 + i03 * c1)
+                       (-i30 * s5 + i32 * s2 - i33 * s1)
+                       (i20 * s5 - i22 * s2 + i23 * s1))
+                   (V4 (i10 * c4 - i11 * c2 + i13 * c0)
+                       (-i00 * c4 + i01 * c2 - i03 * c0)
+                       (i30 * s4 - i31 * s2 + i33 * s0)
+                       (-i20 * s4 + i21 * s2 - i23 * s0))
+                   (V4 (-i10 * c3 + i11 * c1 - i12 * c0)
+                       (i00 * c3 - i01 * c1 + i02 * c0)
+                       (-i30 * s3 + i31 * s1 - i32 * s0)
+                       (i20 * s3 - i21 * s1 + i22 * s0))
+{-# INLINE inv44 #-}
+
+-- | Compute the (L, U) decomposition of a square matrix using Crout's
+--   algorithm. The 'Index' of the vectors must be 'Integral'.
+lu :: ( Num a
+      , Fractional a
+      , Foldable m
+      , Traversable m
+      , Applicative m
+      , Additive m
+      , Ixed (m a)
+      , Ixed (m (m a))
+      , i ~ Index (m a)
+      , i ~ Index (m (m a))
+      , Eq i
+      , Integral i
+      , a ~ IxValue (m a)
+      , m a ~ IxValue (m (m a))
+      , Num (m a)
+      )
+   => m (m a)
+   -> (m (m a), m (m a))
+lu a =
+    let n = fromIntegral (length a)
+        initU = identity
+        initL = zero
+        buildLVal !i !j !l !u =
+            let go !k !s
+                    | k == j = s
+                    | otherwise = go (k+1)
+                                     ( s
+                                      + ( (l ^?! ix i ^?! ix k)
+                                        * (u ^?! ix k ^?! ix j)
+                                        )
+                                      )
+                s' = go 0 0
+            in l & (ix i . ix j) .~ ((a ^?! ix i ^?! ix j) - s')
+        buildL !i !j !l !u
+            | i == n = l
+            | otherwise = buildL (i+1) j (buildLVal i j l u) u
+        buildUVal !i !j !l !u =
+            let go !k !s
+                    | k == j = s
+                    | otherwise = go (k+1)
+                                     ( s
+                                     + ( (l ^?! ix j ^?! ix k)
+                                       * (u ^?! ix k ^?! ix i)
+                                       )
+                                     )
+                s' = go 0 0
+            in u & (ix j . ix i) .~ ( ((a ^?! ix j ^?! ix i) - s')
+                                    / (l ^?! ix j ^?! ix j)
+                                    )
+        buildU !i !j !l !u
+            | i == n = u
+            | otherwise = buildU (i+1) j l (buildUVal i j l u)
+        buildLU !j !l !u
+            | j == n = (l, u)
+            | otherwise =
+                let l' = buildL j j l u
+                    u' = buildU j j l' u
+                in buildLU (j+1) l' u'
+    in buildLU 0 initL initU
+
+-- | Compute the (L, U) decomposition of a square matrix using Crout's
+--   algorithm, using the vector's 'Finite' instance to provide an index.
+luFinite :: ( Num a
+            , Fractional a
+            , Functor m
+            , Finite m
+            , n ~ Size m
+            , KnownNat n
+            , Num (m a)
+            )
+         => m (m a)
+         -> (m (m a), m (m a))
+luFinite a =
+    bimap (fmap fromV . fromV)
+          (fmap fromV . fromV)
+          (lu (fmap toV (toV a)))
+
+-- | Solve a linear system with a lower-triangular matrix of coefficients with
+--   forwards substitution.
+forwardSub :: ( Num a
+              , Fractional a
+              , Foldable m
+              , Additive m
+              , Ixed (m a)
+              , Ixed (m (m a))
+              , i ~ Index (m a)
+              , i ~ Index (m (m a))
+              , Eq i
+              , Ord i
+              , Integral i
+              , a ~ IxValue (m a)
+              , m a ~ IxValue (m (m a))
+              )
+           => m (m a)
+           -> m a
+           -> m a
+forwardSub a b =
+    let n = fromIntegral (length b)
+        initX = zero
+        coeff !i !j !s !x
+            | j == i = s
+            | otherwise = coeff i (j+1) (s + ((a ^?! ix i ^?! ix j) * (x ^?! ix j))) x
+        go !i !x
+            | i == n = x
+            | otherwise = go (i + 1) (x & ix i .~ ( ((b ^?! ix i) - coeff i 0 0 x)
+                                                  / (a ^?! ix i ^?! ix i)
+                                                  ))
+    in go 0 initX
+
+-- | Solve a linear system with a lower-triangular matrix of coefficients with
+--   forwards substitution, using the vector's 'Finite' instance to provide an
+--   index.
+forwardSubFinite :: ( Num a
+                    , Fractional a
+                    , Foldable m
+                    , n ~ Size m
+                    , KnownNat n
+                    , Additive m
+                    , Finite m
+                    )
+                 => m (m a)
+                 -> m a
+                 -> m a
+forwardSubFinite a b = fromV (forwardSub (fmap toV (toV a)) (toV b))
+
+-- | Solve a linear system with an upper-triangular matrix of coefficients with
+--   backwards substitution.
+backwardSub :: ( Num a
+               , Fractional a
+               , Foldable m
+               , Additive m
+               , Ixed (m a)
+               , Ixed (m (m a))
+               , i ~ Index (m a)
+               , i ~ Index (m (m a))
+               , Eq i
+               , Ord i
+               , Integral i
+               , a ~ IxValue (m a)
+               , m a ~ IxValue (m (m a))
+               )
+            => m (m a)
+            -> m a
+            -> m a
+backwardSub a b =
+    let n = fromIntegral (length b)
+        initX = zero
+        coeff !i !j !s !x
+            | j == n = s
+            | otherwise = coeff i
+                                (j+1)
+                                (s + ((a ^?! ix i ^?! ix j) * (x ^?! ix j)))
+                                x
+        go !i !x
+            | i < 0 = x
+            | otherwise = go (i-1)
+                             (x & ix i .~ ( ((b ^?! ix i) - coeff i (i+1) 0 x)
+                                          / (a ^?! ix i ^?! ix i)
+                                          ))
+    in go (n-1) initX
+
+-- | Solve a linear system with an upper-triangular matrix of coefficients with
+--   backwards substitution, using the vector's 'Finite' instance to provide an
+--   index.
+backwardSubFinite :: ( Num a
+                     , Fractional a
+                     , Foldable m
+                     , n ~ Size m
+                     , KnownNat n
+                     , Additive m
+                     , Finite m
+                     )
+                  => m (m a)
+                  -> m a
+                  -> m a
+backwardSubFinite a b = fromV (backwardSub (fmap toV (toV a)) (toV b))
+
+-- | Solve a linear system with LU decomposition.
+luSolve :: ( Num a
+           , Fractional a
+           , Foldable m
+           , Traversable m
+           , Applicative m
+           , Additive m
+           , Ixed (m a)
+           , Ixed (m (m a))
+           , i ~ Index (m a)
+           , i ~ Index (m (m a))
+           , Eq i
+           , Integral i
+           , a ~ IxValue (m a)
+           , m a ~ IxValue (m (m a))
+           , Num (m a)
+           )
+        => m (m a)
+        -> m a
+        -> m a
+luSolve a b =
+    let (l, u) = lu a
+    in backwardSub u (forwardSub l b)
+
+-- | Solve a linear system with LU decomposition, using the vector's 'Finite'
+--   instance to provide an index.
+luSolveFinite :: ( Num a
+                 , Fractional a
+                 , Functor m
+                 , Finite m
+                 , n ~ Size m
+                 , KnownNat n
+                 , Num (m a)
+                 )
+              => m (m a)
+              -> m a
+              -> m a
+luSolveFinite a b = fromV (luSolve (fmap toV (toV a)) (toV b))
+
+-- | Invert a matrix with LU decomposition.
+luInv :: ( Num a
+         , Fractional a
+         , Foldable m
+         , Traversable m
+         , Applicative m
+         , Additive m
+         , Distributive m
+         , Ixed (m a)
+         , Ixed (m (m a))
+         , i ~ Index (m a)
+         , i ~ Index (m (m a))
+         , Eq i
+         , Integral i
+         , a ~ IxValue (m a)
+         , m a ~ IxValue (m (m a))
+         , Num (m a)
+         )
+      => m (m a)
+      -> m (m a)
+luInv a =
+    let n = fromIntegral (length a)
+        initA' = zero
+        (l, u) = lu a
+        go !i !a'
+            | i == n = a'
+            | otherwise = let e   = zero & ix i .~ 1
+                              a'r = backwardSub u (forwardSub l e)
+                          in go (i+1) (a' & ix i .~ a'r)
+    in transpose (go 0 initA')
+
+-- | Invert a matrix with LU decomposition, using the vector's 'Finite' instance
+--   to provide an index.
+luInvFinite :: ( Num a
+               , Fractional a
+               , Functor m
+               , Finite m
+               , n ~ Size m
+               , KnownNat n
+               , Num (m a)
+               )
+            => m (m a)
+            -> m (m a)
+luInvFinite a = fmap fromV (fromV (luInv (fmap toV (toV a))))
+
+-- | Compute the determinant of a matrix using LU decomposition.
+luDet :: ( Num a
+         , Fractional a
+         , Foldable m
+         , Traversable m
+         , Applicative m
+         , Additive m
+         , Trace m
+         , Ixed (m a)
+         , Ixed (m (m a))
+         , i ~ Index (m a)
+         , i ~ Index (m (m a))
+         , Eq i
+         , Integral i
+         , a ~ IxValue (m a)
+         , m a ~ IxValue (m (m a))
+         , Num (m a)
+         )
+      => m (m a)
+      -> a
+luDet a =
+    let (l, u) = lu a
+        p      = Foldable.foldl (*) 1
+    in p (diagonal l) * p (diagonal u)
+
+-- | Compute the determinant of a matrix using LU decomposition, using the
+--   vector's 'Finite' instance to provide an index.
+luDetFinite :: ( Num a
+               , Fractional a
+               , Functor m
+               , Finite m
+               , n ~ Size m
+               , KnownNat n
+               , Num (m a)
+               )
+            => m (m a)
+            -> a
+luDetFinite = luDet . fmap toV . toV
diff --git a/src/Linear/Metric.hs b/src/Linear/Metric.hs
--- a/src/Linear/Metric.hs
+++ b/src/Linear/Metric.hs
@@ -1,8 +1,9 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DefaultSignatures #-}
+{-# LANGUAGE Trustworthy #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Metric
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -12,16 +13,25 @@
 -- Free metric spaces
 ----------------------------------------------------------------------------
 module Linear.Metric
-  ( Metric(..), normalize
+  ( Metric(..), normalize, project
   ) where
 
+import Control.Applicative
 import Data.Foldable as Foldable
-import Data.Functor.Apply
+import Data.Functor.Compose
+import Data.Functor.Identity
+import Data.Functor.Product
+import Data.Vector (Vector)
+import Data.IntMap (IntMap)
+import Data.Map (Map)
+import Data.HashMap.Strict (HashMap)
+import Data.Hashable (Hashable)
 import Linear.Epsilon
 import Linear.Vector
 
 -- $setup
 -- >>> import Linear
+--
 
 -- | Free and sparse inner product/metric spaces.
 class Additive f => Metric f where
@@ -31,8 +41,10 @@
   -- >>> V2 1 2 `dot` V2 3 4
   -- 11
   dot :: Num a => f a -> f a -> a
+#ifndef HLINT
   default dot :: (Foldable f, Num a) => f a -> f a -> a
-  dot x y = Foldable.sum $ liftF2 (*) x y
+  dot x y = Foldable.sum $ liftI2 (*) x y
+#endif
 
   -- | Compute the squared norm. The name quadrance arises from
   -- Norman J. Wildberger's rational trigonometry.
@@ -56,8 +68,43 @@
   signorm v = fmap (/m) v where
     m = norm v
 
+instance (Metric f, Metric g) => Metric (Product f g) where
+  dot (Pair a b) (Pair c d) = dot a c + dot b d
+  quadrance (Pair a b) = quadrance a + quadrance b
+  qd (Pair a b) (Pair c d) = qd a c + qd b d
+  distance p q = sqrt (qd p q)
+
+instance (Metric f, Metric g) => Metric (Compose f g) where
+  dot (Compose a) (Compose b) = quadrance (liftI2 dot a b)
+  quadrance = quadrance . fmap quadrance . getCompose
+  qd (Compose a) (Compose b) = quadrance (liftI2 qd a b)
+  distance (Compose a) (Compose b) = norm (liftI2 qd a b)
+
+instance Metric Identity where
+  dot (Identity x) (Identity y) = x * y
+
+instance Metric []
+
+instance Metric Maybe
+
+instance Metric ZipList where
+  -- ZipList is missing its Foldable instance
+  dot (ZipList x) (ZipList y) = dot x y
+
+instance Metric IntMap
+
+instance Ord k => Metric (Map k)
+
+instance (Hashable k, Eq k) => Metric (HashMap k)
+
+instance Metric Vector
+
 -- | Normalize a 'Metric' functor to have unit 'norm'. This function
 -- does not change the functor if its 'norm' is 0 or 1.
 normalize :: (Floating a, Metric f, Epsilon a) => f a -> f a
 normalize v = if nearZero l || nearZero (1-l) then v else fmap (/sqrt l) v
   where l = quadrance v
+
+-- | @project u v@ computes the projection of @v@ onto @u@.
+project :: (Metric v, Fractional a) => v a -> v a -> v a
+project u v = ((v `dot` u) / quadrance u) *^ u
diff --git a/src/Linear/Plucker.hs b/src/Linear/Plucker.hs
--- a/src/Linear/Plucker.hs
+++ b/src/Linear/Plucker.hs
@@ -1,8 +1,17 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Plucker
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -17,36 +26,109 @@
   , isotropic
   , (><)
   , plucker
+  , plucker3D
+  -- * Operations on lines
+  , parallel
   , intersects
+  , LinePass(..)
+  , passes
+  , quadranceToOrigin
+  , closestToOrigin
+  , isLine
+  , coincides
+  , coincides'
   -- * Basis elements
   ,      p01, p02, p03
   , p10,      p12, p13
   , p20, p21,      p23
   , p30, p31, p32
+
+  , e01, e02, e03, e12, e31, e23
   ) where
 
+#if !MIN_VERSION_base(4,18,0)
 import Control.Applicative
+#endif
+import Control.DeepSeq (NFData(rnf))
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens hiding (index, (<.>))
+import Data.Binary as Binary
+import Data.Bytes.Serial
 import Data.Distributive
 import Data.Foldable as Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
 import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
 import Data.Semigroup
 import Data.Semigroup.Foldable
-import Data.Semigroup.Traversable
-import Data.Traversable
+import Data.Serialize as Cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Foreign.Ptr (castPtr)
 import Foreign.Storable (Storable(..))
 import GHC.Arr (Ix(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
 import Linear.Epsilon
 import Linear.Metric
+import Linear.V
+import Linear.V2
+import Linear.V3
 import Linear.V4
 import Linear.Vector
-
-{-# ANN module "HLint: ignore Reduce duplication" #-}
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 
 -- | Plücker coordinates for lines in a 3-dimensional space.
-data Plucker a = Plucker a a a a a a deriving (Eq,Ord,Show,Read)
+data Plucker a = Plucker !a !a !a !a !a !a deriving (Eq,Ord,Show,Read
+                                                    ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+                                                    ,Lift
+#endif
+                                                    )
 
+instance Finite Plucker where
+  type Size Plucker = 6
+  toV (Plucker a b c d e f) = V (V.fromListN 6 [a,b,c,d,e,f])
+  fromV (V v) = Plucker (v V.! 0) (v V.! 1) (v V.! 2) (v V.! 3) (v V.! 4) (v V.! 5)
+
+instance Random a => Random (Plucker a) where
+  random g = case random g of
+    (a, g1) -> case random g1 of
+      (b, g2) -> case random g2 of
+        (c, g3) -> case random g3 of
+          (d, g4) -> case random g4 of
+            (e, g5) -> case random g5 of
+              (f, g6) -> (Plucker a b c d e f, g6)
+  randomR (Plucker a b c d e f, Plucker a' b' c' d' e' f') g = case randomR (a,a') g of
+    (a'', g1) -> case randomR (b,b') g1 of
+      (b'', g2) -> case randomR (c,c') g2 of
+        (c'', g3) -> case randomR (d,d') g3 of
+          (d'', g4) -> case randomR (e,e') g4 of
+            (e'', g5) -> case randomR (f,f') g5 of
+              (f'', g6) -> (Plucker a'' b'' c'' d'' e'' f'', g6)
+
+instance Uniform a => Uniform (Plucker a) where
+
+instance UniformRange a => UniformRange (Plucker a) where
+  uniformRM (Plucker a b c d e f, Plucker a' b' c' d' e' f') g = Plucker
+    <$> uniformRM (a, a') g
+    <*> uniformRM (b, b') g
+    <*> uniformRM (c, c') g
+    <*> uniformRM (d, d') g
+    <*> uniformRM (e, e') g
+    <*> uniformRM (f, f') g
+
 instance Functor Plucker where
   fmap g (Plucker a b c d e f) = Plucker (g a) (g b) (g c) (g d) (g e) (g f)
   {-# INLINE fmap #-}
@@ -63,7 +145,13 @@
     Plucker (a g) (b h) (c i) (d j) (e k) (f l)
   {-# INLINE (<*>) #-}
 
-instance Additive Plucker
+instance Additive Plucker where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
 instance Bind Plucker where
   Plucker a b c d e f >>- g = Plucker a' b' c' d' e' f' where
@@ -76,8 +164,10 @@
   {-# INLINE (>>-) #-}
 
 instance Monad Plucker where
+#if !(MIN_VERSION_base(4,11,0))
   return a = Plucker a a a a a a
   {-# INLINE return #-}
+#endif
   Plucker a b c d e f >>= g = Plucker a' b' c' d' e' f' where
     Plucker a' _ _ _ _ _ = g a
     Plucker _ b' _ _ _ _ = g b
@@ -96,14 +186,19 @@
                          (fmap (\(Plucker _ _ _ _ _ x) -> x) f)
   {-# INLINE distribute #-}
 
-instance Core Plucker where
-  core f = Plucker (f p01) (f p02) (f p03) (f p23) (f p31) (f p12)
-  {-# INLINE core #-}
+instance Representable Plucker where
+  type Rep Plucker = E Plucker
+  tabulate f = Plucker (f e01) (f e02) (f e03) (f e23) (f e31) (f e12)
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
 
 instance Foldable Plucker where
   foldMap g (Plucker a b c d e f) =
     g a `mappend` g b `mappend` g c `mappend` g d `mappend` g e `mappend` g f
   {-# INLINE foldMap #-}
+  null _ = False
+  length _ =  6
 
 instance Traversable Plucker where
   traverse g (Plucker a b c d e f) =
@@ -170,6 +265,48 @@
   fromRational = pure . fromRational
   {-# INLINE fromRational #-}
 
+instance Floating a => Floating (Plucker a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    (**) = liftA2 (**)
+    {-# INLINE (**) #-}
+    logBase = liftA2 logBase
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
+instance Hashable a => Hashable (Plucker a) where
+  hashWithSalt s (Plucker a b c d e f) = s `hashWithSalt` a `hashWithSalt` b `hashWithSalt` c `hashWithSalt` d `hashWithSalt` e `hashWithSalt` f
+  {-# INLINE hashWithSalt #-}
+
 instance Storable a => Storable (Plucker a) where
   sizeOf _ = 6 * sizeOf (undefined::a)
   {-# INLINE sizeOf #-}
@@ -193,30 +330,46 @@
     where ptr' = castPtr ptr
   {-# INLINE peek #-}
 
--- | Given a pair of points represented by homogeneous coordinates generate Plücker coordinates
--- for the line through them.
+instance Metric Plucker where
+  dot (Plucker a b c d e f) (Plucker g h i j k l) = a*g+b*h+c*i+d*j+e*k+f*l
+  {-# INLINE dot #-}
+
+instance Epsilon a => Epsilon (Plucker a) where
+  nearZero = nearZero . quadrance
+  {-# INLINE nearZero #-}
+
+-- | Given a pair of points represented by homogeneous coordinates
+-- generate Plücker coordinates for the line through them, directed
+-- from the second towards the first.
 plucker :: Num a => V4 a -> V4 a -> Plucker a
 plucker (V4 a b c d)
         (V4 e f g h) =
   Plucker (a*f-b*e)
           (a*g-c*e)
-          (a*d-h*e)
-          (c*h-d*g)
-          (d*f-b*h)
           (b*g-c*f)
+          (a*h-d*e)
+          (b*h-d*f)
+          (c*h-d*g)
 {-# INLINE plucker #-}
 
+-- | Given a pair of 3D points, generate Plücker coordinates for the
+-- line through them, directed from the second towards the first.
+plucker3D :: Num a => V3 a -> V3 a -> Plucker a
+plucker3D p q = Plucker a b c d e f
+  where V3 a b c = p - q
+        V3 d e f = p `cross` q
+
 -- | These elements form a basis for the Plücker space, or the Grassmanian manifold @Gr(2,V4)@.
 --
 -- @
--- 'p01' :: Lens' ('Plucker' a) a
--- 'p02' :: Lens' ('Plucker' a) a
--- 'p03' :: Lens' ('Plucker' a) a
--- 'p23' :: Lens' ('Plucker' a) a
--- 'p31' :: Lens' ('Plucker' a) a
--- 'p12' :: Lens' ('Plucker' a) a
+-- 'p01' :: 'Lens'' ('Plucker' a) a
+-- 'p02' :: 'Lens'' ('Plucker' a) a
+-- 'p03' :: 'Lens'' ('Plucker' a) a
+-- 'p23' :: 'Lens'' ('Plucker' a) a
+-- 'p31' :: 'Lens'' ('Plucker' a) a
+-- 'p12' :: 'Lens'' ('Plucker' a) a
 -- @
-p01, p02, p03, p23, p31, p12 :: Functor f => (a -> f a) -> Plucker a -> f (Plucker a)
+p01, p02, p03, p23, p31, p12 :: Lens' (Plucker a) a
 p01 g (Plucker a b c d e f) = (\a' -> Plucker a' b c d e f) <$> g a
 p02 g (Plucker a b c d e f) = (\b' -> Plucker a b' c d e f) <$> g b
 p03 g (Plucker a b c d e f) = (\c' -> Plucker a b c' d e f) <$> g c
@@ -233,12 +386,12 @@
 -- | These elements form an alternate basis for the Plücker space, or the Grassmanian manifold @Gr(2,V4)@.
 --
 -- @
--- 'p10' :: 'Num' a => Lens' ('Plucker' a) a
--- 'p20' :: 'Num' a => Lens' ('Plucker' a) a
--- 'p30' :: 'Num' a => Lens' ('Plucker' a) a
--- 'p32' :: 'Num' a => Lens' ('Plucker' a) a
--- 'p13' :: 'Num' a => Lens' ('Plucker' a) a
--- 'p21' :: 'Num' a => Lens' ('Plucker' a) a
+-- 'p10' :: 'Num' a => 'Lens'' ('Plucker' a) a
+-- 'p20' :: 'Num' a => 'Lens'' ('Plucker' a) a
+-- 'p30' :: 'Num' a => 'Lens'' ('Plucker' a) a
+-- 'p32' :: 'Num' a => 'Lens'' ('Plucker' a) a
+-- 'p13' :: 'Num' a => 'Lens'' ('Plucker' a) a
+-- 'p21' :: 'Num' a => 'Lens'' ('Plucker' a) a
 -- @
 p10, p20, p30, p32, p13, p21 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
 p10 = anti p01
@@ -257,35 +410,296 @@
 anti :: (Functor f, Num a) => ((a -> f a) -> r) -> (a -> f a) -> r
 anti k f = k (fmap negate . f . negate)
 
+e01, e02, e03, e23, e31, e12 :: E Plucker
+e01 = E p01
+e02 = E p02
+e03 = E p03
+e23 = E p23
+e31 = E p31
+e12 = E p12
+
+instance WithIndex.FunctorWithIndex (E Plucker) Plucker where
+  imap f (Plucker a b c d e g) = Plucker (f e01 a) (f e02 b) (f e03 c) (f e23 d) (f e31 e) (f e12 g)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E Plucker) Plucker where
+  ifoldMap f (Plucker a b c d e g) = f e01 a `mappend` f e02 b `mappend` f e03 c
+                           `mappend` f e23 d `mappend` f e31 e `mappend` f e12 g
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E Plucker) Plucker where
+  itraverse f (Plucker a b c d e g) = Plucker <$> f e01 a <*> f e02 b <*> f e03 c
+                                              <*> f e23 d <*> f e31 e <*> f e12 g
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E Plucker) Plucker where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E Plucker) Plucker where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E Plucker) Plucker where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (Plucker a) = E Plucker
+type instance IxValue (Plucker a) = a
+
+instance Ixed (Plucker a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (Plucker a) (Plucker b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+
 -- | Valid Plücker coordinates @p@ will have @'squaredError' p '==' 0@
 --
 -- That said, floating point makes a mockery of this claim, so you may want to use 'nearZero'.
-squaredError :: (Eq a, Num a) => Plucker a -> a
+squaredError :: Num a => Plucker a -> a
 squaredError v = v >< v
 {-# INLINE squaredError #-}
 
 -- | This isn't th actual metric because this bilinear form gives rise to an isotropic quadratic space
 infixl 5 ><
 (><) :: Num a => Plucker a -> Plucker a -> a
-Plucker a b c d e f >< Plucker g h i j k l = a*g+b*h+c*i-d*j-e*k-f*l
+Plucker a b c d e f >< Plucker g h i j k l = a*l-b*k+c*j+d*i-e*h+f*g
 {-# INLINE (><) #-}
 
--- | Checks if the line is near-isotropic (isotropic vectors in this quadratic space represent lines in real 3d space)
+-- | Checks if the line is near-isotropic (isotropic vectors in this
+-- quadratic space represent lines in real 3d space).
 isotropic :: Epsilon a => Plucker a -> Bool
 isotropic a = nearZero (a >< a)
 {-# INLINE isotropic #-}
 
--- | Checks if the two vectors intersect (or nearly intersect)
-intersects :: Epsilon a => Plucker a -> Plucker a -> Bool
-intersects a b = nearZero (a >< b)
+-- | Checks if two lines intersect (or nearly intersect).
+intersects :: (Epsilon a, Ord a) => Plucker a -> Plucker a -> Bool
+intersects a b = not (a `parallel` b) && passes a b == Coplanar
+-- intersects :: Epsilon a => Plucker a -> Plucker a -> Bool
+-- intersects a b = nearZero (a >< b)
 {-# INLINE intersects #-}
 
-instance Metric Plucker where
-  dot (Plucker a b c d e f) (Plucker g h i j k l) = a*g+b*h+c*i+d*j+e*k+f*l
-  {-# INLINE dot #-}
+-- | Describe how two lines pass each other.
+data LinePass = Coplanar
+              -- ^ The lines are coplanar (parallel or intersecting).
+              | Clockwise
+              -- ^ The lines pass each other clockwise (right-handed
+              -- screw)
+              | Counterclockwise
+              -- ^ The lines pass each other counterclockwise
+              -- (left-handed screw).
+                deriving (Eq, Show,Generic)
 
-instance Epsilon a => Epsilon (Plucker a) where
-  nearZero = nearZero . quadrance
-  {-# INLINE nearZero #-}
+-- | Check how two lines pass each other. @passes l1 l2@ describes
+-- @l2@ when looking down @l1@.
+passes :: (Epsilon a, Ord a) => Plucker a -> Plucker a -> LinePass
+passes a b
+  | nearZero s = Coplanar
+  | s > 0 = Counterclockwise
+  | otherwise = Clockwise
+  where s = (u1 `dot` v2) + (u2 `dot` v1)
+        V2 u1 v1 = toUV a
+        V2 u2 v2 = toUV b
+{-# INLINE passes #-}
 
+-- | Checks if two lines are parallel.
+parallel :: Epsilon a => Plucker a -> Plucker a -> Bool
+parallel a b = nearZero $ u1 `cross` u2
+  where V2 u1 _ = toUV a
+        V2 u2 _ = toUV b
+{-# INLINE parallel #-}
+
+-- | Represent a Plücker coordinate as a pair of 3-tuples, typically
+-- denoted U and V.
+toUV :: Plucker a -> V2 (V3 a)
+toUV (Plucker a b c d e f) = V2 (V3 a b c) (V3 d e f)
+
+-- | Checks if two lines coincide in space. In other words, undirected equality.
+coincides :: (Epsilon a, Fractional a) => Plucker a -> Plucker a -> Bool
+coincides p1 p2 = Foldable.all nearZero $ (s *^ p2) - p1
+  where s = maybe 1 getFirst . getOptionCompat . fold $ saveDiv <$> p1 <*> p2
+        saveDiv x y | nearZero y = optionCompat Nothing
+                    | otherwise  = optionCompat . Just $ First (x / y)
+{-# INLINABLE coincides #-}
+
+-- | Checks if two lines coincide in space, and have the same
+-- orientation.
+coincides' :: (Epsilon a, Fractional a, Ord a) => Plucker a -> Plucker a -> Bool
+coincides' p1 p2 = Foldable.all nearZero ((s *^ p2) - p1) && s > 0
+  where s = maybe 1 getFirst . getOptionCompat . fold $ saveDiv <$> p1 <*> p2
+        saveDiv x y | nearZero y = optionCompat Nothing
+                    | otherwise  = optionCompat . Just $ First (x / y)
+{-# INLINABLE coincides' #-}
+
+-- The coincides and coincides' functions above require the use of a Maybe type
+-- with the following Monoid instance:
+--
+--   instance Semigroup a => Monoid (Maybe a) where ...
+--
+-- Unfortunately, Maybe has only had such an instance since base-4.11. Prior
+-- to that, its Monoid instance had an instance context of Monoid a, which is
+-- too strong. To compensate, we use CPP to define an OptionCompat type
+-- synonym, which is an alias for Maybe on recent versions of base and an alias
+-- for Data.Semigroup.Option on older versions of base. We don't want to use
+-- Option on recent versions of base, as it is deprecated.
+#if MIN_VERSION_base(4,11,0)
+type OptionCompat = Maybe
+
+optionCompat :: Maybe a -> OptionCompat a
+optionCompat = id
+
+getOptionCompat :: OptionCompat a -> Maybe a
+getOptionCompat = id
+#else
+type OptionCompat = Option
+
+optionCompat :: Maybe a -> OptionCompat a
+optionCompat = Option
+
+getOptionCompat :: OptionCompat a -> Maybe a
+getOptionCompat = getOption
+#endif
+
+-- | The minimum squared distance of a line from the origin.
+quadranceToOrigin :: Fractional a => Plucker a -> a
+quadranceToOrigin p = (v `dot` v) / (u `dot` u)
+  where V2 u v = toUV p
+{-# INLINE quadranceToOrigin #-}
+
+-- | The point where a line is closest to the origin.
+closestToOrigin :: Fractional a => Plucker a -> V3 a
+closestToOrigin p = normalizePoint $ V4 x y z (u `dot` u)
+  where V2 u v = toUV p
+        V3 x y z = v `cross` u
+{-# INLINE closestToOrigin #-}
+
+-- | Not all 6-dimensional points correspond to a line in 3D. This
+-- predicate tests that a Plücker coordinate lies on the Grassmann
+-- manifold, and does indeed represent a 3D line.
+isLine :: Epsilon a => Plucker a -> Bool
+isLine p = nearZero $ u `dot` v
+  where V2 u v = toUV p
+{-# INLINE isLine #-}
+
 -- TODO: drag some more stuff out of my thesis
+
+data instance U.Vector    (Plucker a) =  V_Plucker !Int (U.Vector    a)
+data instance U.MVector s (Plucker a) = MV_Plucker !Int (U.MVector s a)
+instance U.Unbox a => U.Unbox (Plucker a)
+
+instance U.Unbox a => M.MVector U.MVector (Plucker a) where
+  basicLength (MV_Plucker n _) = n
+  basicUnsafeSlice m n (MV_Plucker _ v) = MV_Plucker n (M.basicUnsafeSlice (6*m) (6*n) v)
+  basicOverlaps (MV_Plucker _ v) (MV_Plucker _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_Plucker n) (M.basicUnsafeNew (6*n))
+  basicUnsafeRead (MV_Plucker _ a) i =
+    do let o = 6*i
+       x <- M.basicUnsafeRead a o
+       y <- M.basicUnsafeRead a (o+1)
+       z <- M.basicUnsafeRead a (o+2)
+       w <- M.basicUnsafeRead a (o+3)
+       v <- M.basicUnsafeRead a (o+4)
+       u <- M.basicUnsafeRead a (o+5)
+       return (Plucker x y z w v u)
+  basicUnsafeWrite (MV_Plucker _ a) i (Plucker x y z w v u) =
+    do let o = 6*i
+       M.basicUnsafeWrite a o     x
+       M.basicUnsafeWrite a (o+1) y
+       M.basicUnsafeWrite a (o+2) z
+       M.basicUnsafeWrite a (o+3) w
+       M.basicUnsafeWrite a (o+4) v
+       M.basicUnsafeWrite a (o+5) u
+  basicInitialize (MV_Plucker _ v) = M.basicInitialize v
+
+instance U.Unbox a => G.Vector U.Vector (Plucker a) where
+  basicUnsafeFreeze (MV_Plucker n v) = liftM ( V_Plucker n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_Plucker n v) = liftM (MV_Plucker n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_Plucker n _) = n
+  basicUnsafeSlice m n (V_Plucker _ v) = V_Plucker n (G.basicUnsafeSlice (6*m) (6*n) v)
+  basicUnsafeIndexM (V_Plucker _ a) i =
+    do let o = 6*i
+       x <- G.basicUnsafeIndexM a o
+       y <- G.basicUnsafeIndexM a (o+1)
+       z <- G.basicUnsafeIndexM a (o+2)
+       w <- G.basicUnsafeIndexM a (o+3)
+       v <- G.basicUnsafeIndexM a (o+4)
+       u <- G.basicUnsafeIndexM a (o+5)
+       return (Plucker x y z w v u)
+
+instance MonadZip Plucker where
+  mzipWith = liftA2
+
+instance MonadFix Plucker where
+  mfix f = Plucker (let Plucker a _ _ _ _ _ = f a in a)
+                   (let Plucker _ a _ _ _ _ = f a in a)
+                   (let Plucker _ _ a _ _ _ = f a in a)
+                   (let Plucker _ _ _ a _ _ = f a in a)
+                   (let Plucker _ _ _ _ a _ = f a in a)
+                   (let Plucker _ _ _ _ _ a = f a in a)
+
+instance NFData a => NFData (Plucker a) where
+  rnf (Plucker a b c d e f) = rnf a `seq` rnf b `seq` rnf c
+                        `seq` rnf d `seq` rnf e `seq` rnf f
+
+instance Serial1 Plucker where
+  serializeWith = traverse_
+  deserializeWith k = Plucker <$> k <*> k <*> k <*> k <*> k <*> k
+
+instance Serial a => Serial (Plucker a) where
+  serialize = serializeWith serialize
+  deserialize = deserializeWith deserialize
+
+instance Binary a => Binary (Plucker a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (Plucker a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 Plucker where
+  liftEq k (Plucker a1 b1 c1 d1 e1 f1)
+           (Plucker a2 b2 c2 d2 e2 f2)
+         = k a1 a2 && k b1 b2 && k c1 c2 && k d1 d2 && k e1 e2 && k f1 f2
+instance Ord1 Plucker where
+  liftCompare k (Plucker a1 b1 c1 d1 e1 f1)
+                (Plucker a2 b2 c2 d2 e2 f2)
+            = k a1 a2 `mappend` k b1 b2 `mappend` k c1 c2 `mappend` k d1 d2 `mappend` k e1 e2 `mappend` k f1 f2
+instance Read1 Plucker where
+  liftReadsPrec k _ z = readParen (z > 10) $ \r ->
+     [ (Plucker a b c d e f, r7)
+     | ("Plucker",r1) <- lex r
+     , (a,r2) <- k 11 r1
+     , (b,r3) <- k 11 r2
+     , (c,r4) <- k 11 r3
+     , (d,r5) <- k 11 r4
+     , (e,r6) <- k 11 r5
+     , (f,r7) <- k 11 r6
+     ]
+instance Show1 Plucker where
+  liftShowsPrec k _ z (Plucker a b c d e f) = showParen (z > 10) $
+     showString "Plucker " . k 11 a . showChar ' ' . k 11 b . showChar ' ' . k 11 c . showChar ' ' . k 11 d . showChar ' ' . k 11 e . showChar ' ' . k 11 f
+
+instance Field1 (Plucker a) (Plucker a) a a where
+  _1 f (Plucker x y z u v w) = f x <&> \x' -> Plucker x' y z u v w
+
+instance Field2 (Plucker a) (Plucker a) a a where
+  _2 f (Plucker x y z u v w) = f y <&> \y' -> Plucker x y' z u v w
+
+instance Field3 (Plucker a) (Plucker a) a a where
+  _3 f (Plucker x y z u v w) = f z <&> \z' -> Plucker x y z' u v w
+
+instance Field4 (Plucker a) (Plucker a) a a where
+  _4 f (Plucker x y z u v w) = f u <&> \u' -> Plucker x y z u' v w
+
+instance Field5 (Plucker a) (Plucker a) a a where
+  _5 f (Plucker x y z u v w) = f v <&> \v' -> Plucker x y z u v' w
+
+instance Field6 (Plucker a) (Plucker a) a a where
+  _6 f (Plucker x y z u v w) = f w <&> \w' -> Plucker x y z u v w'
+
+instance Semigroup a => Semigroup (Plucker a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (Plucker a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
diff --git a/src/Linear/Plucker/Coincides.hs b/src/Linear/Plucker/Coincides.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Plucker/Coincides.hs
@@ -0,0 +1,38 @@
+{-# LANGUAGE GADTs #-}
+---------------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2012-2015 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- Utility for working with Plücker coordinates for lines in 3d homogeneous space.
+----------------------------------------------------------------------------------
+module Linear.Plucker.Coincides
+  ( Coincides(..)
+  ) where
+
+import Linear.Epsilon
+import Linear.Plucker
+
+-- | When lines are represented as Plücker coordinates, we have the
+-- ability to check for both directed and undirected
+-- equality. Undirected equality between 'Line's (or a 'Line' and a
+-- 'Ray') checks that the two lines coincide in 3D space. Directed
+-- equality, between two 'Ray's, checks that two lines coincide in 3D,
+-- and have the same direction. To accomodate these two notions of
+-- equality, we use an 'Eq' instance on the 'Coincides' data type.
+--
+-- For example, to check the /directed/ equality between two lines,
+-- @p1@ and @p2@, we write, @Ray p1 == Ray p2@.
+data Coincides a where
+  Line :: (Epsilon a, Fractional a) => Plucker a -> Coincides a
+  Ray  :: (Epsilon a, Fractional a, Ord a) => Plucker a -> Coincides a
+
+instance Eq (Coincides a) where
+  Line a == Line b  = coincides a b
+  Line a == Ray b   = coincides a b
+  Ray a  == Line b  = coincides a b
+  Ray a  == Ray b   = coincides' a b
diff --git a/src/Linear/Projection.hs b/src/Linear/Projection.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Projection.hs
@@ -0,0 +1,260 @@
+{-# LANGUAGE CPP #-}
+---------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2015 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- Common projection matrices: e.g. perspective/orthographic transformation
+-- matrices.
+--
+-- Analytically derived inverses are also supplied, because they can be
+-- much more accurate in practice than computing them through general
+-- purpose means
+---------------------------------------------------------------------------
+module Linear.Projection
+  ( lookAt
+  , perspective, inversePerspective
+  , infinitePerspective, inverseInfinitePerspective
+  , frustum, inverseFrustum
+  , ortho, inverseOrtho
+  ) where
+
+import Control.Lens hiding (index)
+import Linear.V3
+import Linear.V4
+import Linear.Matrix
+import Linear.Epsilon
+import Linear.Metric
+
+-- $setup
+-- >>> import Linear.Matrix
+-- >>> import Linear.V2
+-- >>> import Linear.V4
+
+-- | Build a look at view matrix
+lookAt
+  :: (Epsilon a, Floating a)
+  => V3 a -- ^ Eye
+  -> V3 a -- ^ Center
+  -> V3 a -- ^ Up
+  -> M44 a
+lookAt eye center up =
+  V4 (V4 (xa^._x)  (xa^._y)  (xa^._z)  xd)
+     (V4 (ya^._x)  (ya^._y)  (ya^._z)  yd)
+     (V4 (-za^._x) (-za^._y) (-za^._z) zd)
+     (V4 0         0         0          1)
+  where za = normalize $ center - eye
+        xa = normalize $ cross za up
+        ya = cross xa za
+        xd = -dot xa eye
+        yd = -dot ya eye
+        zd = dot za eye
+
+-- | Build a matrix for a symmetric perspective-view frustum
+perspective
+  :: Floating a
+  => a -- ^ FOV (y direction, in radians)
+  -> a -- ^ Aspect ratio
+  -> a -- ^ Near plane
+  -> a -- ^ Far plane
+  -> M44 a
+perspective fovy aspect near far =
+  V4 (V4 x 0 0    0)
+     (V4 0 y 0    0)
+     (V4 0 0 z    w)
+     (V4 0 0 (-1) 0)
+  where tanHalfFovy = tan $ fovy / 2
+        x = 1 / (aspect * tanHalfFovy)
+        y = 1 / tanHalfFovy
+        fpn = far + near
+        fmn = far - near
+        oon = 0.5/near
+        oof = 0.5/far
+        -- z = 1 / (near/fpn - far/fpn) -- would be better by .5 bits
+        z = -fpn/fmn
+        w = 1/(oof-oon) -- 13 bits error reduced to 0.17
+        -- w = -(2 * far * near) / fmn
+
+#ifdef HERBIE
+{-# ANN perspective "NoHerbie" #-}
+#endif
+
+-- | Build an inverse perspective matrix
+inversePerspective
+  :: Floating a
+  => a -- ^ FOV (y direction, in radians)
+  -> a -- ^ Aspect ratio
+  -> a -- ^ Near plane
+  -> a -- ^ Far plane
+  -> M44 a
+inversePerspective fovy aspect near far =
+  V4 (V4 a 0 0 0   )
+     (V4 0 b 0 0   )
+     (V4 0 0 0 (-1))
+     (V4 0 0 c d   )
+  where tanHalfFovy = tan $ fovy / 2
+        a = aspect * tanHalfFovy
+        b = tanHalfFovy
+        c = oon - oof
+        d = oon + oof
+        oon = 0.5/near
+        oof = 0.5/far
+
+
+-- | Build a perspective matrix per the classic @glFrustum@ arguments.
+frustum
+  :: Floating a
+  => a -- ^ Left
+  -> a -- ^ Right
+  -> a -- ^ Bottom
+  -> a -- ^ Top
+  -> a -- ^ Near
+  -> a -- ^ Far
+  -> M44 a
+frustum l r b t n f =
+  V4 (V4 x 0 a    0)
+     (V4 0 y e    0)
+     (V4 0 0 c    d)
+     (V4 0 0 (-1) 0)
+  where
+    rml = r-l
+    tmb = t-b
+    fmn = f-n
+    x = 2*n/rml
+    y = 2*n/tmb
+    a = (r+l)/rml
+    e = (t+b)/tmb
+    c = negate (f+n)/fmn
+    d = (-2*f*n)/fmn
+
+inverseFrustum
+  :: Floating a
+  => a -- ^ Left
+  -> a -- ^ Right
+  -> a -- ^ Bottom
+  -> a -- ^ Top
+  -> a -- ^ Near
+  -> a -- ^ Far
+  -> M44 a
+inverseFrustum l r b t n f =
+  V4 (V4 rx 0 0 ax)
+     (V4 0 ry 0 by)
+     (V4 0 0 0 (-1))
+     (V4 0 0 rd cd)
+  where
+    hrn  = 0.5/n
+    hrnf = 0.5/(n*f)
+    rx = (r-l)*hrn
+    ry = (t-b)*hrn
+    ax = (r+l)*hrn
+    by = (t+b)*hrn
+    cd = (f+n)*hrnf
+    rd = (n-f)*hrnf
+
+-- | Build a matrix for a symmetric perspective-view frustum with a far plane at infinite
+infinitePerspective
+  :: Floating a
+  => a -- ^ FOV (y direction, in radians)
+  -> a -- ^ Aspect Ratio
+  -> a -- ^ Near plane
+  -> M44 a
+infinitePerspective fovy a n =
+  V4 (V4 x 0 0    0)
+     (V4 0 y 0    0)
+     (V4 0 0 (-1) w)
+     (V4 0 0 (-1) 0)
+  where
+    t = n*tan(fovy/2)
+    b = -t
+    l = b*a
+    r = t*a
+    x = (2*n)/(r-l)
+    y = (2*n)/(t-b)
+    w = -2*n
+
+inverseInfinitePerspective
+  :: Floating a
+  => a -- ^ FOV (y direction, in radians)
+  -> a -- ^ Aspect Ratio
+  -> a -- ^ Near plane
+  -> M44 a
+inverseInfinitePerspective fovy a n =
+  V4 (V4 rx 0 0  0)
+     (V4 0 ry 0  0)
+     (V4 0 0  0  (-1))
+     (V4 0 0  rw (-rw))
+  where
+    t = n*tan(fovy/2)
+    b = -t
+    l = b*a
+    r = t*a
+    hrn = 0.5/n
+    rx = (r-l)*hrn
+    ry = (t-b)*hrn
+    rw = -hrn
+
+-- | Build an orthographic perspective matrix from 6 clipping planes.
+-- This matrix takes the region delimited by these planes and maps it
+-- to normalized device coordinates between [-1,1]
+--
+-- This call is designed to mimic the parameters to the OpenGL @glOrtho@
+-- call, so it has a slightly strange convention: Notably: the near and
+-- far planes are negated.
+--
+-- Consequently:
+--
+-- @
+-- 'ortho' l r b t n f !* 'V4' l b (-n) 1 = 'V4' (-1) (-1) (-1) 1
+-- 'ortho' l r b t n f !* 'V4' r t (-f) 1 = 'V4' 1 1 1 1
+-- @
+--
+-- Examples:
+--
+-- >>> ortho 1 2 3 4 5 6 !* V4 1 3 (-5) 1
+-- V4 (-1.0) (-1.0) (-1.0) 1.0
+--
+-- >>> ortho 1 2 3 4 5 6 !* V4 2 4 (-6) 1
+-- V4 1.0 1.0 1.0 1.0
+ortho
+  :: Fractional a
+  => a -- ^ Left
+  -> a -- ^ Right
+  -> a -- ^ Bottom
+  -> a -- ^ Top
+  -> a -- ^ Near
+  -> a -- ^ Far
+  -> M44 a
+ortho l r b t n f =
+  V4 (V4 (-2*x) 0      0     ((r+l)*x))
+     (V4 0      (-2*y) 0     ((t+b)*y))
+     (V4 0      0      (2*z) ((f+n)*z))
+     (V4 0      0      0     1)
+  where x = recip(l-r)
+        y = recip(b-t)
+        z = recip(n-f)
+
+-- | Build an inverse orthographic perspective matrix from 6 clipping planes
+inverseOrtho
+  :: Fractional a
+  => a -- ^ Left
+  -> a -- ^ Right
+  -> a -- ^ Bottom
+  -> a -- ^ Top
+  -> a -- ^ Near
+  -> a -- ^ Far
+  -> M44 a
+inverseOrtho l r b t n f =
+  V4 (V4 x 0 0 c)
+     (V4 0 y 0 d)
+     (V4 0 0 z e)
+     (V4 0 0 0 1)
+  where x = 0.5*(r-l)
+        y = 0.5*(t-b)
+        z = 0.5*(n-f)
+        c = 0.5*(l+r)
+        d = 0.5*(b+t)
+        e = -0.5*(n+f)
diff --git a/src/Linear/Quaternion.hs b/src/Linear/Quaternion.hs
--- a/src/Linear/Quaternion.hs
+++ b/src/Linear/Quaternion.hs
@@ -1,8 +1,18 @@
-{-# LANGUAGE DeriveDataTypeable, PatternGuards, ScopedTypeVariables #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE PatternGuards #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Quaternion
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -15,6 +25,7 @@
   ( Quaternion(..)
   , Complicated(..)
   , Hamiltonian(..)
+  , ee, ei, ej, ek
   , slerp
   , asinq
   , acosq
@@ -29,31 +40,82 @@
   ) where
 
 import Control.Applicative
+import Control.DeepSeq (NFData(rnf))
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens hiding ((<.>))
+import Data.Binary as Binary
+import Data.Bytes.Serial
 import Data.Complex (Complex((:+)))
 import Data.Data
 import Data.Distributive
-import Data.Traversable
 import Data.Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
 import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
+#if !(MIN_VERSION_base(4,11,0))
+import Data.Semigroup (Semigroup(..))
+#endif
+import Data.Serialize as Cereal
 import GHC.Arr (Ix(..))
 import qualified Data.Foldable as F
-import Data.Monoid
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Foreign.Ptr (castPtr, plusPtr)
 import Foreign.Storable (Storable(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
 import Linear.Epsilon
 import Linear.Conjugate
 import Linear.Metric
+import Linear.V
+import Linear.V2
 import Linear.V3
+import Linear.V4
 import Linear.Vector
 import Prelude hiding (any)
-
-{-# ANN module "HLint: ignore Reduce duplication" #-}
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 
 -- | Quaternions
-data Quaternion a = Quaternion a {-# UNPACK #-}!(V3 a)
-                    deriving (Eq,Ord,Read,Show,Data,Typeable)
+data Quaternion a = Quaternion !a {-# UNPACK #-}!(V3 a)
+                    deriving (Eq,Ord,Read,Show,Data
+                             ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+                             ,Lift
+#endif
+                             )
 
+instance Finite Quaternion where
+  type Size Quaternion = 4
+  toV (Quaternion a (V3 b c d)) = V (V.fromListN 4 [a, b, c, d])
+  fromV (V v) = Quaternion (v V.! 0) (V3 (v V.! 1) (v V.! 2) (v V.! 3))
+
+instance Random a => Random (Quaternion a) where
+  random g = case random g of
+    (a, g') -> case random g' of
+      (b, g'') -> (Quaternion a b, g'')
+  randomR (Quaternion a b, Quaternion c d) g = case randomR (a,c) g of
+    (e, g') -> case randomR (b,d) g' of
+      (f, g'') -> (Quaternion e f, g'')
+
+instance Uniform a => Uniform (Quaternion a) where
+
+instance UniformRange a => UniformRange (Quaternion a) where
+  uniformRM (Quaternion a b, Quaternion c d) g = Quaternion
+    <$> uniformRM (a, c) g
+    <*> uniformRM (b, d) g
+
 instance Functor Quaternion where
   fmap f (Quaternion e v) = Quaternion (f e) (fmap f v)
   {-# INLINE fmap #-}
@@ -70,7 +132,13 @@
   Quaternion f fv <*> Quaternion a v = Quaternion (f a) (fv <*> v)
   {-# INLINE (<*>) #-}
 
-instance Additive Quaternion
+instance Additive Quaternion where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
 instance Bind Quaternion where
   Quaternion a (V3 b c d) >>- f = Quaternion a' (V3 b' c' d') where
@@ -106,15 +174,49 @@
       inRange (l1,u1) i1 && inRange (l2,u2) i2
     {-# INLINE inRange #-}
 
-instance Core Quaternion where
-  core f = Quaternion (f _e) (V3 (f _i) (f _j) (f _k))
-  {-# INLINE core #-}
+instance Representable Quaternion where
+  type Rep Quaternion = E Quaternion
+  tabulate f = Quaternion (f ee) (V3 (f ei) (f ej) (f ek))
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
 
+instance WithIndex.FunctorWithIndex (E Quaternion) Quaternion where
+  imap f (Quaternion a (V3 b c d)) = Quaternion (f ee a) $ V3 (f ei b) (f ej c) (f ek d)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E Quaternion) Quaternion where
+  ifoldMap f (Quaternion a (V3 b c d)) = f ee a `mappend` f ei b `mappend` f ej c `mappend` f ek d
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E Quaternion) Quaternion where
+  itraverse f (Quaternion a (V3 b c d)) = Quaternion <$> f ee a <*> (V3 <$> f ei b <*> f ej c <*> f ek d)
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E Quaternion) Quaternion where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E Quaternion) Quaternion where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E Quaternion) Quaternion where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (Quaternion a) = E Quaternion
+type instance IxValue (Quaternion a) = a
+
+instance Ixed (Quaternion a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (Quaternion a) (Quaternion b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
 instance Foldable Quaternion where
   foldMap f (Quaternion e v) = f e `mappend` foldMap f v
   {-# INLINE foldMap #-}
   foldr f z (Quaternion e v) = f e (F.foldr f z v)
   {-# INLINE foldr #-}
+  null _ = False
+  length _ = 4
 
 instance Traversable Quaternion where
   traverse f (Quaternion e v) = Quaternion <$> f e <*> traverse f v
@@ -167,6 +269,14 @@
       ik = isInfinite k
   {-# INLINE signum #-}
 
+instance Hashable a => Hashable (Quaternion a) where
+  hashWithSalt s (Quaternion a b) = s `hashWithSalt` a `hashWithSalt` b
+  {-# INLINE hashWithSalt #-}
+
+instance Hashable1 Quaternion where
+  liftHashWithSalt h s (Quaternion a b) = liftHashWithSalt h (h s a) b
+  {-# INLINE liftHashWithSalt #-}
+
 qNaN :: RealFloat a => Quaternion a
 qNaN = Quaternion fNaN (V3 fNaN fNaN fNaN) where fNaN = 0/0
 {-# INLINE qNaN #-}
@@ -186,7 +296,7 @@
                    (r0*q3-r1*q2+r2*q1-r3*q0))
                ^/ (r0*r0 + r1*r1 + r2*r2 + r3*r3)
   {-# INLINE (/) #-}
-  recip q = q ^/ quadrance q
+  recip q@(Quaternion e v) = Quaternion e (negate v) ^/ quadrance q
   {-# INLINE recip #-}
   fromRational x = Quaternion (fromRational x) 0
   {-# INLINE fromRational #-}
@@ -197,17 +307,12 @@
 
 -- | A vector space that includes the basis elements '_e' and '_i'
 class Complicated t where
-  -- |
-  -- @
-  -- '_e' :: Lens' (t a) a
-  -- @
-  _e :: Functor f => (a -> f a) -> t a -> f (t a)
-  -- |
-  -- @
-  -- '_i' :: Lens' (t a) a
-  -- @
-  _i :: Functor f => (a -> f a) -> t a -> f (t a)
+  _e, _i :: Lens' (t a) a
 
+ee, ei :: Complicated t => E t
+ee = E _e
+ei = E _i
+
 instance Complicated Complex where
   _e f (a :+ b) = (:+ b) <$> f a
   {-# INLINE _e #-}
@@ -222,22 +327,13 @@
 
 -- | A vector space that includes the basis elements '_e', '_i', '_j' and '_k'
 class Complicated t => Hamiltonian t where
-  -- |
-  -- @
-  -- '_j' :: Lens' (t a) a
-  -- @
-  _j :: Functor f => (a -> f a) -> t a -> f (t a)
-  -- |
-  -- @
-  -- '_k' :: Lens' (t a) a
-  -- @
-  _k :: Functor f => (a -> f a) -> t a -> f (t a)
-  -- |
-  -- @
-  -- '_ijk' :: Lens' (t a) (V3 a)
-  -- @
-  _ijk :: Functor f => (V3 a -> f (V3 a)) -> t a -> f (t a)
+  _j, _k :: Lens' (t a) a
+  _ijk :: Lens' (t a) (V3 a)
 
+ej, ek :: Hamiltonian t => E t
+ej = E _j
+ek = E _k
+
 instance Hamiltonian Quaternion where
   _j f (Quaternion a v) = Quaternion a <$> _y f v
   {-# INLINE _j #-}
@@ -280,6 +376,29 @@
 pow q t = exp (t *^ log q)
 {-# INLINE pow #-}
 
+sqrte2pqiq :: (Floating a, Ord a) => a -> a -> a
+sqrte2pqiq e qiq -- = sqrt (e*e + qiq)
+  | e < - 1.5097698010472593e153 = -(qiq/e) - e
+  | e < 5.582399551122541e57      = sqrt (e*e + qiq) -- direct definition
+  | otherwise                     = (qiq/e) + e
+-- {-# SPECIALIZE sqrte2pqiq :: Double -> Double -> Double #-}
+-- {-# SPECIALIZE sqrte2pqiq :: Float -> Float -> Float #-}
+#ifdef HERBIE
+{-# ANN sqrte2pqiq "NoHerbie" #-}
+#endif
+
+tanrhs :: (Floating a, Ord a) => a -> a -> a -> a
+tanrhs sai ai d -- = cosh ai * (sai / ai) / d -- improved from 6.04 bits of error to 0.19 bits
+  | sai < -4.618902267687042e-52 = (sai / d / ai) * cosh ai
+  | sai < 1.038530535935153e-39 = (cosh ai * sai) / ai / d
+  | otherwise = (sai / d / ai) * cosh ai
+-- {-# SPECIALIZE tanrhs :: Double -> Double -> Double -> Double #-}
+-- {-# SPECIALIZE tanrhs :: Float -> Float -> Float -> Float #-}
+#ifdef HERBIE
+{-# ANN tanrhs "NoHerbie" #-}
+#endif
+
+
 -- ehh..
 instance RealFloat a => Floating (Quaternion a) where
   {-# SPECIALIZE instance Floating (Quaternion Float) #-}
@@ -288,18 +407,21 @@
   {-# INLINE pi #-}
   exp q@(Quaternion e v)
     | qiq == 0 = Quaternion (exp e) v
-    | ai <- sqrt qiq, ee <- exp e = reimagine (ee * cos ai) (ee * (sin ai / ai)) q
+    | ai <- sqrt qiq, exe <- exp e = reimagine (exe * cos ai) (exe * (sin ai / ai)) q
     where qiq = qi q
   {-# INLINE exp #-}
-  log q@(Quaternion e v@(V3 _i j k))
+  log q@(Quaternion e v)
     | qiq == 0 = if e >= 0
-                 then Quaternion (log e) v
-                 else Quaternion (log (negate e)) (V3 pi j k) -- mmm, pi
-    | ai <- sqrt qiq, m <- sqrt (e*e + qiq) = reimagine (log m) (atan2 m e / ai) q
+                 then Quaternion (log e) v                   -- Using v rather than 0 preserves negative zeros
+                 else Quaternion (negate (log (negate e))) v -- negative scalar: negate quaternion, take log, negate again, preserves negative zeros
+    | ai <- sqrt qiq = reimagine (log m) (acos (e / m) / ai) q
     where qiq = qi q
+          m = sqrte2pqiq e qiq
   {-# INLINE log #-}
+
   x ** y = exp (y * log x)
   {-# INLINE (**) #-}
+
   sqrt q@(Quaternion e v)
     | m   == 0 = q
     | qiq == 0 = if e > 0
@@ -307,38 +429,44 @@
                  else Quaternion 0 (V3 (sqrt (negate e)) 0 0)
     | im <- sqrt (0.5*(m-e)) / sqrt qiq = Quaternion (0.5*(m+e)) (v^*im)
     where qiq = qi q
-          m = sqrt (e*e + qiq)
+          m = sqrte2pqiq e qiq
   {-# INLINE sqrt #-}
+
   cos q@(Quaternion e v)
     | qiq == 0 = Quaternion (cos e) v
-    | ai <- sqrt qiq = reimagine (cos e * cosh ai) (- sin e * (sinh ai / ai)) q
+    | ai <- sqrt qiq = reimagine (cos e * cosh ai) (- sin e / ai / sinh ai) q -- 0.15 bits error
     where qiq = qi q
   {-# INLINE cos #-}
+
   sin q@(Quaternion e v)
     | qiq == 0 = Quaternion (sin e) v
-    | ai <- sqrt qiq = reimagine (sin e * cosh ai) (cos e * (sinh ai / ai)) q
+    | ai <- sqrt qiq = reimagine (sin e * cosh ai) (cos e * sinh ai / ai) q
     where qiq = qi q
   {-# INLINE sin #-}
+
   tan q@(Quaternion e v)
     | qiq == 0 = Quaternion (tan e) v
     | ai <- sqrt qiq, ce <- cos e, sai <- sinh ai, d <- ce*ce + sai*sai =
-      reimagine (ce * sin e / d) (cosh ai * (sai / ai) / d) q
+      reimagine (ce * sin e / d) (tanrhs sai ai d) q
     where qiq = qi q
   {-# INLINE tan #-}
+
   sinh q@(Quaternion e v)
     | qiq == 0 = Quaternion (sinh e) v
-    | ai <- sqrt qiq = reimagine (sinh e * cos ai) (cosh e * (sin ai / ai)) q
+    | ai <- sqrt qiq = reimagine (sinh e * cos ai) (cosh e * sin ai / ai) q
     where qiq = qi q
   {-# INLINE sinh #-}
+
   cosh q@(Quaternion e v)
     | qiq == 0 = Quaternion (cosh e) v
-    | ai <- sqrt qiq = reimagine (cosh e * cos ai) ((sinh e * sin ai) / ai) q
+    | ai <- sqrt qiq = reimagine (cosh e * cos ai) (sin ai * (sinh e / ai)) q
     where qiq = qi q
   {-# INLINE cosh #-}
+
   tanh q@(Quaternion e v)
     | qiq == 0 = Quaternion (tanh e) v
     | ai <- sqrt qiq, se <- sinh e, cai <- cos ai, d <- se*se + cai*cai =
-      reimagine ((cosh e * se) / d) ((cai * (sin ai / ai)) / d) q
+      reimagine (cosh e * se / d) (tanhrhs cai ai d) q
     where qiq = qi q
   {-# INLINE tanh #-}
 
@@ -356,6 +484,15 @@
   atanh = cut atanh
   {-# INLINE atanh #-}
 
+tanhrhs :: (Floating a, Ord a) => a -> a -> a -> a
+tanhrhs cai ai d -- = cai * (sin ai / ai) / d
+  | d >= -4.2173720203427147e-29 && d < 4.446702369113811e64 = cai / (d * (ai / sin ai))
+  | otherwise                                                = cai * (1 / ai / sin ai) / d
+-- {-# SPECIALIZE tanhrhs :: Double -> Double -> Double -> Double #-}
+-- {-# SPECIALIZE tanhrhs :: Float -> Float -> Float -> Float #-}
+#ifdef HERBIE
+{-# ANN tanhrhs "NoHerbie" #-}
+#endif
 
 -- | Helper for calculating with specific branch cuts
 cut :: RealFloat a => (Complex a -> Complex a) -> Quaternion a -> Quaternion a
@@ -424,14 +561,15 @@
 {-# INLINE atanhq #-}
 
 -- | Spherical linear interpolation between two quaternions.
+
 slerp :: RealFloat a => Quaternion a -> Quaternion a -> a -> Quaternion a
 slerp q p t
   | 1.0 - cosphi < 1e-8 = q
-  | phi <- acos cosphi, r <- recip (sin phi)
-  = (sin ((1-t)*phi)*r *^ q ^+^ f (sin (t*phi)*r) *^ p) ^/ sin phi
+  | otherwise           = ((sin ((1-t)*phi) *^ q) + sin (t*phi) *^ f p) ^/ sin phi
   where
-   dqp = dot q p
-   (cosphi, f) = if dqp < 0 then (-dqp, negate) else (dqp, id)
+    dqp = dot q p
+    (cosphi, f) = if dqp < 0 then (-dqp, negate) else (dqp, id)
+    phi = acos cosphi
 {-# SPECIALIZE slerp :: Quaternion Float -> Quaternion Float -> Float -> Quaternion Float #-}
 {-# SPECIALIZE slerp :: Quaternion Double -> Quaternion Double -> Double -> Quaternion Double #-}
 
@@ -449,6 +587,117 @@
 -- | @'axisAngle' axis theta@ builds a 'Quaternion' representing a
 -- rotation of @theta@ radians about @axis@.
 axisAngle :: (Epsilon a, Floating a) => V3 a -> a -> Quaternion a
-axisAngle axis theta = normalize $ Quaternion (cos half) $ sin half *^ axis
+axisAngle axis theta = Quaternion (cos half) (sin half *^ normalize axis)
   where half = theta / 2
 {-# INLINE axisAngle #-}
+
+data instance U.Vector    (Quaternion a) =  V_Quaternion !Int (U.Vector    a)
+data instance U.MVector s (Quaternion a) = MV_Quaternion !Int (U.MVector s a)
+instance U.Unbox a => U.Unbox (Quaternion a)
+
+instance U.Unbox a => M.MVector U.MVector (Quaternion a) where
+  basicLength (MV_Quaternion n _) = n
+  basicUnsafeSlice m n (MV_Quaternion _ v) = MV_Quaternion n (M.basicUnsafeSlice (4*m) (4*n) v)
+  basicOverlaps (MV_Quaternion _ v) (MV_Quaternion _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_Quaternion n) (M.basicUnsafeNew (4*n))
+  basicUnsafeRead (MV_Quaternion _ v) i =
+    do let o = 4*i
+       x <- M.basicUnsafeRead v o
+       y <- M.basicUnsafeRead v (o+1)
+       z <- M.basicUnsafeRead v (o+2)
+       w <- M.basicUnsafeRead v (o+3)
+       return (Quaternion x (V3 y z w))
+  basicUnsafeWrite (MV_Quaternion _ v) i (Quaternion x (V3 y z w)) =
+    do let o = 4*i
+       M.basicUnsafeWrite v o     x
+       M.basicUnsafeWrite v (o+1) y
+       M.basicUnsafeWrite v (o+2) z
+       M.basicUnsafeWrite v (o+3) w
+  basicInitialize (MV_Quaternion _ v) = M.basicInitialize v
+
+instance U.Unbox a => G.Vector U.Vector (Quaternion a) where
+  basicUnsafeFreeze (MV_Quaternion n v) = liftM ( V_Quaternion n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_Quaternion n v) = liftM (MV_Quaternion n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_Quaternion n _) = n
+  basicUnsafeSlice m n (V_Quaternion _ v) = V_Quaternion n (G.basicUnsafeSlice (4*m) (4*n) v)
+  basicUnsafeIndexM (V_Quaternion _ v) i =
+    do let o = 4*i
+       x <- G.basicUnsafeIndexM v o
+       y <- G.basicUnsafeIndexM v (o+1)
+       z <- G.basicUnsafeIndexM v (o+2)
+       w <- G.basicUnsafeIndexM v (o+3)
+       return (Quaternion x (V3 y z w))
+
+instance MonadZip Quaternion where
+  mzipWith = liftA2
+
+instance MonadFix Quaternion where
+  mfix f = Quaternion (let Quaternion a _ = f a in a)
+                      (V3 (let Quaternion _ (V3 a _ _) = f a in a)
+                          (let Quaternion _ (V3 _ a _) = f a in a)
+                          (let Quaternion _ (V3 _ _ a) = f a in a))
+
+instance NFData a => NFData (Quaternion a) where
+  rnf (Quaternion a b) = rnf a `seq` rnf b
+
+instance Serial1 Quaternion where
+  serializeWith f (Quaternion a b) = f a >> serializeWith f b
+  deserializeWith f = Quaternion <$> f <*> deserializeWith f
+
+instance Serial a => Serial (Quaternion a) where
+  serialize = serializeWith serialize
+  deserialize = deserializeWith deserialize
+
+instance Binary a => Binary (Quaternion a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (Quaternion a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 Quaternion where
+  liftEq f (Quaternion a b) (Quaternion c d) = f a c && liftEq f b d
+instance Ord1 Quaternion where
+  liftCompare f (Quaternion a b) (Quaternion c d) = f a c `mappend` liftCompare f b d
+instance Show1 Quaternion where
+  liftShowsPrec f g d (Quaternion a b) = showsBinaryWith f (liftShowsPrec f g) "Quaternion" d a b
+instance Read1 Quaternion where
+  liftReadsPrec f g = readsData $ readsBinaryWith f (liftReadsPrec f g) "Quaternion" Quaternion
+
+instance Field1 (Quaternion a) (Quaternion a) a a where
+  _1 f (Quaternion w xyz) = f w <&> \w' -> Quaternion w' xyz
+
+instance Field2 (Quaternion a) (Quaternion a) a a where
+  _2 f (Quaternion w (V3 x y z)) = f x <&> \x' -> Quaternion w (V3 x' y z)
+
+instance Field3 (Quaternion a) (Quaternion a) a a where
+  _3 f (Quaternion w (V3 x y z)) = f y <&> \y' -> Quaternion w (V3 x y' z)
+
+instance Field4 (Quaternion a) (Quaternion a) a a where
+  _4 f (Quaternion w (V3 x y z)) = f z <&> \z' -> Quaternion w (V3 x y z')
+
+instance Semigroup a => Semigroup (Quaternion a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (Quaternion a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
+
+instance R1 Quaternion where
+  _x f (Quaternion w (V3 x y z)) = f x <&> \x' -> Quaternion w (V3 x' y z)
+
+instance R2 Quaternion where
+  _y f (Quaternion w (V3 x y z)) = f y <&> \y' -> Quaternion w (V3 x y' z)
+  _xy f (Quaternion w (V3 x y z)) = f (V2 x y) <&> \(V2 x' y') -> Quaternion w (V3 x' y' z)
+
+instance R3 Quaternion where
+  _z f (Quaternion w (V3 x y z)) = f z <&> \z' -> Quaternion w (V3 x y z')
+  _xyz f (Quaternion w xyz) = Quaternion w <$> f xyz
+
+instance R4 Quaternion where
+  _w f (Quaternion w xyz) = f w <&> \w' -> Quaternion w' xyz
+  _xyzw f (Quaternion w (V3 x y z)) = f (V4 x y z w) <&> \(V4 x' y' z' w') -> Quaternion w' (V3 x' y' z')
+
diff --git a/src/Linear/Trace.hs b/src/Linear/Trace.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/Trace.hs
@@ -0,0 +1,116 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE DefaultSignatures #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE Trustworthy #-}
+---------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2012-2015 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- Simple matrix operation for low-dimensional primitives.
+---------------------------------------------------------------------------
+module Linear.Trace
+  ( Trace(..)
+  , frobenius
+  ) where
+
+import Control.Monad as Monad
+import Linear.V0
+import Linear.V1
+import Linear.V2
+import Linear.V3
+import Linear.V4
+import Linear.Plucker
+import Linear.Quaternion
+import Linear.V
+import Linear.Vector
+import Data.Complex
+import Data.Distributive
+import Data.Foldable as Foldable
+import Data.Functor.Bind as Bind
+import Data.Functor.Compose
+import Data.Functor.Product
+import Data.Hashable
+import Data.HashMap.Lazy
+import Data.IntMap (IntMap)
+import Data.Map (Map)
+
+-- $setup
+-- >>> import Data.Complex
+-- >>> import Debug.SimpleReflect.Vars
+-- >>> import Linear.V2
+
+class Functor m => Trace m where
+  -- | Compute the trace of a matrix
+  --
+  -- >>> trace (V2 (V2 a b) (V2 c d))
+  -- a + d
+  trace :: Num a => m (m a) -> a
+#ifndef HLINT
+  default trace :: (Foldable m, Num a) => m (m a) -> a
+  trace = Foldable.sum . diagonal
+  {-# INLINE trace #-}
+#endif
+
+  -- | Compute the diagonal of a matrix
+  --
+  -- >>> diagonal (V2 (V2 a b) (V2 c d))
+  -- V2 a d
+  diagonal :: m (m a) -> m a
+#ifndef HLINT
+  default diagonal :: Monad m => m (m a) -> m a
+  diagonal = Monad.join
+  {-# INLINE diagonal #-}
+#endif
+
+instance Trace IntMap where
+  diagonal = Bind.join
+  {-# INLINE diagonal #-}
+
+instance Ord k => Trace (Map k) where
+  diagonal = Bind.join
+  {-# INLINE diagonal #-}
+
+instance (Eq k, Hashable k) => Trace (HashMap k) where
+  diagonal = Bind.join
+  {-# INLINE diagonal #-}
+
+instance Dim n => Trace (V n)
+instance Trace V0
+instance Trace V1
+instance Trace V2
+instance Trace V3
+instance Trace V4
+instance Trace Plucker
+instance Trace Quaternion
+
+instance Trace Complex where
+  trace ((a :+ _) :+ (_ :+ b)) = a + b
+  {-# INLINE trace #-}
+  diagonal ((a :+ _) :+ (_ :+ b)) = a :+ b
+  {-# INLINE diagonal #-}
+
+instance (Trace f, Trace g) => Trace (Product f g) where
+  trace (Pair xx yy) = trace (pfst <$> xx) + trace (psnd <$> yy) where
+    pfst (Pair x _) = x
+    psnd (Pair _ y) = y
+  {-# INLINE trace #-}
+  diagonal (Pair xx yy) = diagonal (pfst <$> xx) `Pair` diagonal (psnd <$> yy) where
+    pfst (Pair x _) = x
+    psnd (Pair _ y) = y
+  {-# INLINE diagonal #-}
+
+instance (Distributive g, Trace g, Trace f) => Trace (Compose g f) where
+  trace = trace . fmap (fmap trace . distribute) . getCompose . fmap getCompose
+  {-# INLINE trace #-}
+  diagonal = Compose . fmap diagonal . diagonal . fmap distribute . getCompose . fmap getCompose
+  {-# INLINE diagonal #-}
+
+-- | Compute the <http://mathworld.wolfram.com/FrobeniusNorm.html Frobenius norm> of a matrix.
+frobenius :: (Num a, Foldable f, Additive f, Additive g, Distributive g, Trace g) => f (g a) -> a
+frobenius m = trace $ fmap (\ f' -> Foldable.foldl' (^+^) zero $ liftI2 (*^) f' m) (distribute m)
diff --git a/src/Linear/V.hs b/src/Linear/V.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/V.hs
@@ -0,0 +1,594 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE DefaultSignatures #-}
+{-# LANGUAGE Rank2Types #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE EmptyDataDecls #-}
+{-# LANGUAGE MultiParamTypeClasses, FlexibleContexts, FlexibleInstances, UndecidableInstances #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE RoleAnnotations #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2012-2015 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- n-D Vectors
+----------------------------------------------------------------------------
+
+module Linear.V
+  ( V(V,toVector)
+#ifdef MIN_VERSION_template_haskell
+  , int
+#endif
+  , dim
+  , Dim(..)
+  , reifyDim
+  , reifyVector
+  , reifyDimNat
+  , reifyVectorNat
+  , fromVector
+  , Finite(..)
+  , _V, _V'
+  ) where
+
+import Control.Applicative
+import Control.DeepSeq (NFData)
+import Control.Monad
+import Control.Monad.Fix
+import Control.Monad.Trans.State
+import Control.Monad.Zip
+import Control.Lens as Lens
+import Data.Binary as Binary
+import Data.Bytes.Serial
+import Data.Complex
+import Data.Data
+import Data.Distributive
+import Data.Foldable as Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
+import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep as Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
+import Data.Kind
+import Data.Reflection as R
+import Data.Serialize as Cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import Data.Vector (Vector)
+import Data.Vector.Fusion.Util (Box(..))
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed as U
+import qualified Data.Vector.Generic.Mutable as M
+import Foreign.Ptr
+import Foreign.Storable
+import GHC.TypeLits
+import GHC.Generics (Generic, Generic1)
+#if !(MIN_VERSION_reflection(1,3,0)) && defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH
+#endif
+import Linear.Epsilon
+import Linear.Metric
+import Linear.Vector
+import Prelude as P
+#if !(MIN_VERSION_base(4,11,0))
+import Data.Semigroup
+#endif
+import System.Random (Random(..))
+import System.Random.Stateful (Uniform(..), UniformRange(..))
+
+class Dim n where
+  reflectDim :: p n -> Int
+
+type role V nominal representational
+
+class Finite v where
+  type Size (v :: Type -> Type) :: Nat -- this should allow kind k, for Reifies k Int
+  toV :: v a -> V (Size v) a
+  default toV :: Foldable v => v a -> V (Size v) a
+  toV = V . V.fromList . Foldable.toList
+  fromV :: V (Size v) a -> v a
+
+instance Finite Complex where
+  type Size Complex = 2
+  toV (a :+ b) = V (V.fromListN 2 [a, b])
+  fromV (V v) = (v V.! 0) :+ (v V.! 1)
+
+_V :: (Finite u, Finite v) => Iso (V (Size u) a) (V (Size v) b) (u a) (v b)
+_V = iso fromV toV
+
+_V' :: Finite v => Iso (V (Size v) a) (V (Size v) b) (v a) (v b)
+_V' = iso fromV toV
+
+instance Finite (V (n :: Nat)) where
+  type Size (V n) = n
+  toV = id
+  fromV = id
+
+newtype V n a = V { toVector :: V.Vector a } deriving (Eq,Ord,Show,Read,NFData
+                                                      ,Generic,Generic1
+                                                      )
+
+dim :: forall n a. Dim n => V n a -> Int
+dim _ = reflectDim (Proxy :: Proxy n)
+{-# INLINE dim #-}
+
+instance KnownNat n => Dim (n :: Nat) where
+  reflectDim = fromInteger . natVal
+  {-# INLINE reflectDim #-}
+
+instance (Dim n, Random a) => Random (V n a) where
+  random = runState (V <$> V.replicateM (reflectDim (Proxy :: Proxy n)) (state random))
+  randomR (V ls,V hs) = runState (V <$> V.zipWithM (\l h -> state $ randomR (l,h)) ls hs)
+
+instance (Dim n, Uniform a) => Uniform (V n a) where
+  uniformM g = V <$> V.replicateM (reflectDim (Proxy :: Proxy n)) (uniformM g)
+
+instance (Dim n, UniformRange a) => UniformRange (V n a) where
+  uniformRM (V ls, V hs) g = V <$> V.zipWithM (\l h -> uniformRM (l, h) g) ls hs
+#if (MIN_VERSION_random(1,3,0))
+  isInRange (V ls, V hs) (V xs) = V.and $ V.zipWith3 (\l h x -> isInRange (l, h) x) ls hs xs
+#endif
+
+data ReifiedDim (s :: Type)
+
+retagDim :: (Proxy s -> a) -> proxy (ReifiedDim s) -> a
+retagDim f _ = f Proxy
+{-# INLINE retagDim #-}
+
+instance Reifies s Int => Dim (ReifiedDim s) where
+  reflectDim = retagDim reflect
+  {-# INLINE reflectDim #-}
+
+reifyDimNat :: Int -> (forall (n :: Nat). KnownNat n => Proxy n -> r) -> r
+reifyDimNat i f = R.reifyNat (fromIntegral i) f
+{-# INLINE reifyDimNat #-}
+
+reifyVectorNat :: forall a r. Vector a -> (forall (n :: Nat). KnownNat n => V n a -> r) -> r
+reifyVectorNat v f = reifyNat (fromIntegral $ V.length v) $ \(Proxy :: Proxy n) -> f (V v :: V n a)
+{-# INLINE reifyVectorNat #-}
+
+reifyDim :: Int -> (forall (n :: Type). Dim n => Proxy n -> r) -> r
+reifyDim i f = R.reify i (go f) where
+  go :: (Proxy (ReifiedDim n) -> a) -> proxy n -> a
+  go g _ = g Proxy
+{-# INLINE reifyDim #-}
+
+reifyVector :: forall a r. Vector a -> (forall (n :: Type). Dim n => V n a -> r) -> r
+reifyVector v f = reifyDim (V.length v) $ \(Proxy :: Proxy n) -> f (V v :: V n a)
+{-# INLINE reifyVector #-}
+
+instance Dim n => Dim (V n a) where
+  reflectDim _ = reflectDim (Proxy :: Proxy n)
+  {-# INLINE reflectDim #-}
+
+instance (Dim n, Semigroup a) => Semigroup (V n a) where
+ (<>) = liftA2 (<>)
+
+instance (Dim n, Monoid a) => Monoid (V n a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
+
+instance Functor (V n) where
+  fmap f (V as) = V (fmap f as)
+  {-# INLINE fmap #-}
+
+instance WithIndex.FunctorWithIndex Int (V n) where
+  imap f (V as) = V (Lens.imap f as)
+  {-# INLINE imap #-}
+
+instance Foldable (V n) where
+  fold (V as) = fold as
+  {-# INLINE fold #-}
+  foldMap f (V as) = Foldable.foldMap f as
+  {-# INLINE foldMap #-}
+  foldr f z (V as) = V.foldr f z as
+  {-# INLINE foldr #-}
+  foldl f z (V as) = V.foldl f z as
+  {-# INLINE foldl #-}
+  foldr' f z (V as) = V.foldr' f z as
+  {-# INLINE foldr' #-}
+  foldl' f z (V as) = V.foldl' f z as
+  {-# INLINE foldl' #-}
+  foldr1 f (V as) = V.foldr1 f as
+  {-# INLINE foldr1 #-}
+  foldl1 f (V as) = V.foldl1 f as
+  {-# INLINE foldl1 #-}
+  length (V as) = V.length as
+  {-# INLINE length #-}
+  null (V as) = V.null as
+  {-# INLINE null #-}
+  toList (V as) = V.toList as
+  {-# INLINE toList #-}
+  elem a (V as) = V.elem a as
+  {-# INLINE elem #-}
+  maximum (V as) = V.maximum as
+  {-# INLINE maximum #-}
+  minimum (V as) = V.minimum as
+  {-# INLINE minimum #-}
+  sum (V as) = V.sum as
+  {-# INLINE sum #-}
+  product (V as) = V.product as
+  {-# INLINE product #-}
+
+instance WithIndex.FoldableWithIndex Int (V n) where
+  ifoldMap f (V as) = ifoldMap f as
+  {-# INLINE ifoldMap #-}
+
+instance Traversable (V n) where
+  traverse f (V as) = V <$> traverse f as
+  {-# INLINE traverse #-}
+
+instance WithIndex.TraversableWithIndex Int (V n) where
+  itraverse f (V as) = V <$> itraverse f as
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     Int (V n) where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    Int (V n) where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex Int (V n) where itraverse = WithIndex.itraverse
+#endif
+
+instance Apply (V n) where
+  V as <.> V bs = V (V.zipWith id as bs)
+  {-# INLINE (<.>) #-}
+
+instance Dim n => Applicative (V n) where
+  pure = V . V.replicate (reflectDim (Proxy :: Proxy n))
+  {-# INLINE pure #-}
+
+  V as <*> V bs = V (V.zipWith id as bs)
+  {-# INLINE (<*>) #-}
+
+instance Bind (V n) where
+  V as >>- f = V $ V.generate (V.length as) $ \i ->
+    toVector (f (as `V.unsafeIndex` i)) `V.unsafeIndex` i
+  {-# INLINE (>>-) #-}
+
+instance Dim n => Monad (V n) where
+#if !(MIN_VERSION_base(4,11,0))
+  return = V . V.replicate (reflectDim (Proxy :: Proxy n))
+  {-# INLINE return #-}
+#endif
+  V as >>= f = V $ V.generate (reflectDim (Proxy :: Proxy n)) $ \i ->
+    toVector (f (as `V.unsafeIndex` i)) `V.unsafeIndex` i
+  {-# INLINE (>>=) #-}
+
+instance Dim n => Additive (V n) where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 f (V as) (V bs) = V (V.zipWith f as bs)
+  {-# INLINE liftU2 #-}
+  liftI2 f (V as) (V bs) = V (V.zipWith f as bs)
+  {-# INLINE liftI2 #-}
+
+instance (Dim n, Num a) => Num (V n a) where
+  V as + V bs = V $ V.zipWith (+) as bs
+  {-# INLINE (+) #-}
+  V as - V bs = V $ V.zipWith (-) as bs
+  {-# INLINE (-) #-}
+  V as * V bs = V $ V.zipWith (*) as bs
+  {-# INLINE (*) #-}
+  negate = fmap negate
+  {-# INLINE negate #-}
+  abs = fmap abs
+  {-# INLINE abs #-}
+  signum = fmap signum
+  {-# INLINE signum #-}
+  fromInteger = pure . fromInteger
+  {-# INLINE fromInteger #-}
+
+instance (Dim n, Fractional a) => Fractional (V n a) where
+  recip = fmap recip
+  {-# INLINE recip #-}
+  V as / V bs = V $ V.zipWith (/) as bs
+  {-# INLINE (/) #-}
+  fromRational = pure . fromRational
+  {-# INLINE fromRational #-}
+
+instance (Dim n, Floating a) => Floating (V n a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    V as ** V bs = V $ V.zipWith (**) as bs
+    {-# INLINE (**) #-}
+    logBase (V as) (V bs) = V $ V.zipWith logBase as bs
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
+instance Dim n => Distributive (V n) where
+  distribute f = V $ V.generate (reflectDim (Proxy :: Proxy n)) $ \i -> fmap (\(V v) -> V.unsafeIndex v i) f
+  {-# INLINE distribute #-}
+
+instance Hashable a => Hashable (V n a) where
+  hashWithSalt s0 (V v) =
+    V.foldl' (\s a -> s `hashWithSalt` a) s0 v
+      `hashWithSalt` V.length v
+
+instance Dim n => Hashable1 (V n) where
+  liftHashWithSalt h s0 (V v) =
+    V.foldl' (\s a -> h s a) s0 v
+      `hashWithSalt` V.length v
+  {-# INLINE liftHashWithSalt #-}
+
+instance (Dim n, Storable a) => Storable (V n a) where
+  sizeOf _ = reflectDim (Proxy :: Proxy n) * sizeOf (undefined:: a)
+  {-# INLINE sizeOf #-}
+  alignment _ = alignment (undefined :: a)
+  {-# INLINE alignment #-}
+  poke ptr (V xs) = Foldable.forM_ [0..reflectDim (Proxy :: Proxy n)-1] $ \i ->
+    pokeElemOff ptr' i (V.unsafeIndex xs i)
+    where ptr' = castPtr ptr
+  {-# INLINE poke #-}
+  peek ptr = V <$> V.generateM (reflectDim (Proxy :: Proxy n)) (peekElemOff ptr')
+    where ptr' = castPtr ptr
+  {-# INLINE peek #-}
+
+instance (Dim n, Epsilon a) => Epsilon (V n a) where
+  nearZero = nearZero . quadrance
+  {-# INLINE nearZero #-}
+
+instance Dim n => Metric (V n) where
+  dot (V a) (V b) = V.sum $ V.zipWith (*) a b
+  {-# INLINE dot #-}
+
+-- TODO: instance (Dim n, Ix a) => Ix (V n a)
+
+fromVector :: forall n a. Dim n => Vector a -> Maybe (V n a)
+fromVector v
+  | V.length v == reflectDim (Proxy :: Proxy n) = Just (V v)
+  | otherwise                                   = Nothing
+
+#if !(MIN_VERSION_reflection(1,3,0)) && defined(MIN_VERSION_template_haskell)
+data Z  -- 0
+data D  (n :: *) -- 2n
+data SD (n :: *) -- 2n+1
+data PD (n :: *) -- 2n-1
+
+instance Reifies Z Int where
+  reflect _ = 0
+  {-# INLINE reflect #-}
+
+retagD :: (Proxy n -> a) -> proxy (D n) -> a
+retagD f _ = f Proxy
+{-# INLINE retagD #-}
+
+retagSD :: (Proxy n -> a) -> proxy (SD n) -> a
+retagSD f _ = f Proxy
+{-# INLINE retagSD #-}
+
+retagPD :: (Proxy n -> a) -> proxy (PD n) -> a
+retagPD f _ = f Proxy
+{-# INLINE retagPD #-}
+
+instance Reifies n Int => Reifies (D n) Int where
+  reflect = (\n -> n+n) <$> retagD reflect
+  {-# INLINE reflect #-}
+
+instance Reifies n Int => Reifies (SD n) Int where
+  reflect = (\n -> n+n+1) <$> retagSD reflect
+  {-# INLINE reflect #-}
+
+instance Reifies n Int => Reifies (PD n) Int where
+  reflect = (\n -> n+n-1) <$> retagPD reflect
+  {-# INLINE reflect #-}
+
+-- | This can be used to generate a template haskell splice for a type level version of a given 'int'.
+--
+-- This does not use GHC TypeLits, instead it generates a numeric type by hand similar to the ones used
+-- in the \"Functional Pearl: Implicit Dimurations\" paper by Oleg Kiselyov and Chung-Chieh Shan.
+int :: Int -> TypeQ
+int n = case quotRem n 2 of
+  (0, 0) -> conT ''Z
+  (q,-1) -> conT ''PD `appT` int q
+  (q, 0) -> conT ''D  `appT` int q
+  (q, 1) -> conT ''SD `appT` int q
+  _     -> error "ghc is bad at math"
+#endif
+
+instance Dim n => Representable (V n) where
+  type Rep (V n) = Int
+  tabulate = V . V.generate (reflectDim (Proxy :: Proxy n))
+  {-# INLINE tabulate #-}
+  index (V xs) i = xs V.! i
+  {-# INLINE index #-}
+
+type instance Index (V n a) = Int
+type instance IxValue (V n a) = a
+
+instance Ixed (V n a) where
+  ix i f v@(V as)
+     | i < 0 || i >= V.length as = pure v
+     | otherwise = vLens i f v
+  {-# INLINE ix #-}
+
+instance Dim n => MonadZip (V n) where
+  mzip (V as) (V bs) = V $ V.zip as bs
+  mzipWith f (V as) (V bs) = V $ V.zipWith f as bs
+
+instance Dim n => MonadFix (V n) where
+  mfix f = tabulate $ \r -> let a = Rep.index (f a) r in a
+
+instance Each (V n a) (V n b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+instance (Bounded a, Dim n) => Bounded (V n a) where
+  minBound = pure minBound
+  {-# INLINE minBound #-}
+  maxBound = pure maxBound
+  {-# INLINE maxBound #-}
+
+vConstr :: Constr
+vConstr = mkConstr vDataType "variadic" [] Prefix
+{-# NOINLINE vConstr #-}
+
+vDataType :: DataType
+vDataType = mkDataType "Linear.V.V" [vConstr]
+{-# NOINLINE vDataType #-}
+
+instance (Typeable (V n), Typeable (V n a), Dim n, Data a) => Data (V n a) where
+  gfoldl f z (V as) = z (V . V.fromList) `f` V.toList as
+  toConstr _ = vConstr
+  gunfold k z c = case constrIndex c of
+    1 -> k (z (V . V.fromList))
+    _ -> error "gunfold"
+  dataTypeOf _ = vDataType
+  dataCast1 f = gcast1 f
+
+instance Dim n => Serial1 (V n) where
+  serializeWith = traverse_
+  deserializeWith f = sequenceA $ pure f
+
+instance (Dim n, Serial a) => Serial (V n a) where
+  serialize = traverse_ serialize
+  deserialize = sequenceA $ pure deserialize
+
+instance (Dim n, Binary a) => Binary (V n a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance (Dim n, Serialize a) => Serialize (V n a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 (V n) where
+  liftEq f0 (V as0) (V bs0) = go f0 (V.toList as0) (V.toList bs0) where
+    go _ [] [] = True
+    go f (a:as) (b:bs) = f a b && go f as bs
+    go _ _ _ = False
+
+instance Ord1 (V n) where
+  liftCompare f0 (V as0) (V bs0) = go f0 (V.toList as0) (V.toList bs0) where
+    go f (a:as) (b:bs) = f a b `mappend` go f as bs
+    go _ [] [] = EQ
+    go _ _  [] = GT
+    go _ [] _  = LT
+
+instance Show1 (V n) where
+  liftShowsPrec _ g d (V as) = showParen (d > 10) $ showString "V " . g (V.toList as)
+
+instance Dim n => Read1 (V n) where
+  liftReadsPrec _ g d = readParen (d > 10) $ \r ->
+    [ (V (V.fromList as), r2)
+    | ("V",r1) <- lex r
+    , (as, r2) <- g r1
+    , P.length as == reflectDim (Proxy :: Proxy n)
+    ]
+
+data instance U.Vector    (V n a) =  V_VN {-# UNPACK #-} !Int !(U.Vector    a)
+data instance U.MVector s (V n a) = MV_VN {-# UNPACK #-} !Int !(U.MVector s a)
+instance (Dim n, U.Unbox a) => U.Unbox (V n a)
+
+instance (Dim n, U.Unbox a) => M.MVector U.MVector (V n a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_VN n _) = n
+  basicUnsafeSlice m n (MV_VN _ v) = MV_VN n (M.basicUnsafeSlice (d*m) (d*n) v)
+    where d = reflectDim (Proxy :: Proxy n)
+  basicOverlaps (MV_VN _ v) (MV_VN _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_VN n) (M.basicUnsafeNew (d*n))
+    where d = reflectDim (Proxy :: Proxy n)
+  basicUnsafeRead (MV_VN _ v) i =
+    liftM V $ V.generateM d (\j -> M.basicUnsafeRead v (d*i+j))
+    where d = reflectDim (Proxy :: Proxy n)
+  basicUnsafeWrite (MV_VN _ v0) i (V vn0) = let d0 = V.length vn0 in go v0 vn0 d0 (d0*i) 0
+   where
+    go v vn d o j
+      | j >= d = return ()
+      | otherwise = do
+        a <- liftBox $ G.basicUnsafeIndexM vn j
+        M.basicUnsafeWrite v o a
+        go v vn d (o+1) (j+1)
+  basicInitialize (MV_VN _ v) = M.basicInitialize v
+  {-# INLINE basicInitialize #-}
+
+liftBox :: Monad m => Box a -> m a
+liftBox (Box a) = return a
+{-# INLINE liftBox #-}
+
+instance (Dim n, U.Unbox a) => G.Vector U.Vector (V n a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_VN n v) = liftM ( V_VN n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_VN n v) = liftM (MV_VN n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_VN n _) = n
+  basicUnsafeSlice m n (V_VN _ v) = V_VN n (G.basicUnsafeSlice (d*m) (d*n) v)
+    where d = reflectDim (Proxy :: Proxy n)
+  basicUnsafeIndexM (V_VN _ v) i =
+    liftM V $ V.generateM d (\j -> G.basicUnsafeIndexM v (d*i+j))
+    where d = reflectDim (Proxy :: Proxy n)
+
+vLens :: Int -> Lens' (V n a) a
+vLens i = \f (V v) -> f (v V.! i) <&> \a -> V (v V.// [(i, a)])
+{-# INLINE vLens #-}
+
+instance ( 1 <= n) => Field1  (V n a) (V n a) a a where _1  = vLens  0
+instance ( 2 <= n) => Field2  (V n a) (V n a) a a where _2  = vLens  1
+instance ( 3 <= n) => Field3  (V n a) (V n a) a a where _3  = vLens  2
+instance ( 4 <= n) => Field4  (V n a) (V n a) a a where _4  = vLens  3
+instance ( 5 <= n) => Field5  (V n a) (V n a) a a where _5  = vLens  4
+instance ( 6 <= n) => Field6  (V n a) (V n a) a a where _6  = vLens  5
+instance ( 7 <= n) => Field7  (V n a) (V n a) a a where _7  = vLens  6
+instance ( 8 <= n) => Field8  (V n a) (V n a) a a where _8  = vLens  7
+instance ( 9 <= n) => Field9  (V n a) (V n a) a a where _9  = vLens  8
+instance (10 <= n) => Field10 (V n a) (V n a) a a where _10 = vLens  9
+instance (11 <= n) => Field11 (V n a) (V n a) a a where _11 = vLens 10
+instance (12 <= n) => Field12 (V n a) (V n a) a a where _12 = vLens 11
+instance (13 <= n) => Field13 (V n a) (V n a) a a where _13 = vLens 12
+instance (14 <= n) => Field14 (V n a) (V n a) a a where _14 = vLens 13
+instance (15 <= n) => Field15 (V n a) (V n a) a a where _15 = vLens 14
+instance (16 <= n) => Field16 (V n a) (V n a) a a where _16 = vLens 15
+instance (17 <= n) => Field17 (V n a) (V n a) a a where _17 = vLens 16
+instance (18 <= n) => Field18 (V n a) (V n a) a a where _18 = vLens 17
+instance (19 <= n) => Field19 (V n a) (V n a) a a where _19 = vLens 18
diff --git a/src/Linear/V0.hs b/src/Linear/V0.hs
--- a/src/Linear/V0.hs
+++ b/src/Linear/V0.hs
@@ -1,10 +1,17 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.V0
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -18,22 +25,50 @@
   ) where
 
 import Control.Applicative
+import Control.DeepSeq (NFData(rnf))
+import Control.Lens as Lens
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Data.Binary -- binary
+import Data.Bytes.Serial -- bytes
 import Data.Data
 import Data.Distributive
 import Data.Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
+import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
 import Data.Ix
-import Data.Traversable
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Semigroup
-import Data.Functor.Bind
+#endif
+import Data.Serialize -- cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
 import Foreign.Storable (Storable(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Linear.Metric
 import Linear.Epsilon
 import Linear.Vector
+import Linear.V
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 import Prelude hiding (sum)
 
 -- $setup
+-- >>> import Control.Applicative
 -- >>> import Control.Lens
+-- >>> import qualified Data.Foldable as F
+-- >>> let sum xs = F.sum xs
 
 -- | A 0-dimensional vector
 --
@@ -43,8 +78,45 @@
 -- >>> V0 + V0
 -- V0
 --
-data V0 a = V0 deriving (Eq,Ord,Show,Read,Ix,Enum,Data,Typeable)
+data V0 a = V0 deriving (Eq,Ord,Show,Read,Ix,Enum,Data
+                        ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+                        ,Lift
+#endif
+                        )
 
+instance Finite V0 where
+  type Size V0 = 0
+  toV _ = V V.empty
+  fromV _ = V0
+
+instance Random (V0 a) where
+  random g = (V0, g)
+  randomR _ g = (V0, g)
+  randomRs _ _ = repeat V0
+  randoms _ = repeat V0
+
+instance Uniform (V0 a) where
+
+instance UniformRange (V0 a) where
+  uniformRM (_, _) _ = pure V0
+
+instance Serial1 V0 where
+  serializeWith _ = serialize
+  deserializeWith _ = deserialize
+
+instance Serial (V0 a) where
+  serialize V0 = return ()
+  deserialize = return V0
+
+instance Binary (V0 a) where
+  put V0 = return ()
+  get = return V0
+
+instance Serialize (V0 a) where
+  put V0 = return ()
+  get = return V0
+
 instance Functor V0 where
   fmap _ V0 = V0
   {-# INLINE fmap #-}
@@ -54,6 +126,8 @@
 instance Foldable V0 where
   foldMap _ V0 = mempty
   {-# INLINE foldMap #-}
+  null _ = True
+  length _ = 0
 
 instance Traversable V0 where
   traverse _ V0 = pure V0
@@ -61,23 +135,40 @@
 
 instance Apply V0 where
   V0 <.> V0 = V0
-  {-@ INLINE (<.>) #-}
+  {-# INLINE (<.>) #-}
 
 instance Applicative V0 where
   pure _ = V0
   {-# INLINE pure #-}
   V0 <*> V0 = V0
-  {-@ INLINE (<*>) #-}
+  {-# INLINE (<*>) #-}
 
-instance Additive V0
+instance Semigroup (V0 a) where
+  _ <> _ = V0
 
+instance Monoid (V0 a) where
+  mempty = V0
+#if !(MIN_VERSION_base(4,11,0))
+  mappend _ _ = V0
+#endif
+
+instance Additive V0 where
+  zero = V0
+  {-# INLINE zero #-}
+  liftU2 _ V0 V0 = V0
+  {-# INLINE liftU2 #-}
+  liftI2 _ V0 V0 = V0
+  {-# INLINE liftI2 #-}
+
 instance Bind V0 where
   V0 >>- _ = V0
   {-# INLINE (>>-) #-}
 
 instance Monad V0 where
+#if !(MIN_VERSION_base(4,11,0))
   return _ = V0
   {-# INLINE return #-}
+#endif
   V0 >>= _ = V0
   {-# INLINE (>>=) #-}
 
@@ -105,23 +196,67 @@
   fromRational _ = V0
   {-# INLINE fromRational #-}
 
+instance Floating (V0 a) where
+    pi = V0
+    {-# INLINE pi #-}
+    exp V0 = V0
+    {-# INLINE exp #-}
+    sqrt V0 = V0
+    {-# INLINE sqrt #-}
+    log V0 = V0
+    {-# INLINE log #-}
+    V0 ** V0 = V0
+    {-# INLINE (**) #-}
+    logBase V0 V0 = V0
+    {-# INLINE logBase #-}
+    sin V0 = V0
+    {-# INLINE sin #-}
+    tan V0 = V0
+    {-# INLINE tan #-}
+    cos V0 = V0
+    {-# INLINE cos #-}
+    asin V0 = V0
+    {-# INLINE asin #-}
+    atan V0 = V0
+    {-# INLINE atan #-}
+    acos V0 = V0
+    {-# INLINE acos #-}
+    sinh V0 = V0
+    {-# INLINE sinh #-}
+    tanh V0 = V0
+    {-# INLINE tanh #-}
+    cosh V0 = V0
+    {-# INLINE cosh #-}
+    asinh V0 = V0
+    {-# INLINE asinh #-}
+    atanh V0 = V0
+    {-# INLINE atanh #-}
+    acosh V0 = V0
+    {-# INLINE acosh #-}
+
 instance Metric V0 where
   dot V0 V0 = 0
   {-# INLINE dot #-}
 
-instance Core V0 where
-  core _ = V0
-  {-# INLINE core #-}
-
 instance Distributive V0 where
   distribute _ = V0
   {-# INLINE distribute #-}
 
-instance Epsilon a => Epsilon (V0 a) where
+instance Hashable (V0 a) where
+  hash V0 = 0
+  {-# INLINE hash #-}
+  hashWithSalt s V0 = s
+  {-# INLINE hashWithSalt #-}
+
+instance Hashable1 V0 where
+  liftHashWithSalt _ s V0 = s
+  {-# INLINE liftHashWithSalt #-}
+
+instance Epsilon (V0 a) where
   nearZero _ = True
   {-# INLINE nearZero #-}
 
-instance Storable a => Storable (V0 a) where
+instance Storable (V0 a) where
   sizeOf _ = 0
   {-# INLINE sizeOf #-}
   alignment _ = 1
@@ -130,3 +265,97 @@
   {-# INLINE poke #-}
   peek _ = return V0
   {-# INLINE peek #-}
+
+instance WithIndex.FunctorWithIndex (E V0) V0 where
+  imap _ V0 = V0
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E V0) V0 where
+  ifoldMap _ V0 = mempty
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E V0) V0 where
+  itraverse _ V0 = pure V0
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E V0) V0 where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E V0) V0 where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E V0) V0 where itraverse = WithIndex.itraverse
+#endif
+
+instance Representable V0 where
+  type Rep V0 = E V0
+  tabulate _ = V0
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
+
+type instance Index (V0 a) = E V0
+type instance IxValue (V0 a) = a
+
+instance Ixed (V0 a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (V0 a) (V0 b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+newtype instance U.Vector    (V0 a) = V_V0 Int
+newtype instance U.MVector s (V0 a) = MV_V0 Int
+instance U.Unbox (V0 a)
+
+instance M.MVector U.MVector (V0 a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_V0 n) = n
+  basicUnsafeSlice _ n _ = MV_V0 n
+  basicOverlaps _ _ = False
+  basicUnsafeNew n = return (MV_V0 n)
+  basicUnsafeRead _ _ = return V0
+  basicUnsafeWrite _ _ _ = return ()
+  basicInitialize _ = return ()
+  {-# INLINE basicInitialize #-}
+
+instance G.Vector U.Vector (V0 a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_V0 n) = return (V_V0 n)
+  basicUnsafeThaw (V_V0 n) = return (MV_V0 n)
+  basicLength (V_V0 n) = n
+  basicUnsafeSlice _ n _ = V_V0 n
+  basicUnsafeIndexM _ _ = return V0
+
+instance MonadZip V0 where
+  mzip V0 V0 = V0
+  mzipWith _ V0 V0 = V0
+  munzip V0 = (V0, V0)
+
+instance MonadFix V0 where
+  mfix _ = V0
+
+instance Bounded (V0 a) where
+  minBound = V0
+  {-# INLINE minBound #-}
+  maxBound = V0
+  {-# INLINE maxBound #-}
+
+instance NFData (V0 a) where
+  rnf V0 = ()
+
+instance Eq1 V0   where
+  liftEq _ _ _ = True
+instance Ord1 V0  where
+  liftCompare _ _ _ = EQ
+instance Show1 V0 where
+  liftShowsPrec _ _ = showsPrec
+instance Read1 V0 where
+  liftReadsPrec _ _ = readsPrec
diff --git a/src/Linear/V1.hs b/src/Linear/V1.hs
new file mode 100644
--- /dev/null
+++ b/src/Linear/V1.hs
@@ -0,0 +1,400 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE DeriveFunctor #-}
+{-# LANGUAGE DeriveFoldable #-}
+{-# LANGUAGE DeriveTraversable #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Copyright   :  (C) 2012-2015 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+-- 1-D Vectors
+----------------------------------------------------------------------------
+module Linear.V1
+  ( V1(..)
+  , R1(..)
+  , ex
+  ) where
+
+import Control.Applicative
+import Control.DeepSeq (NFData)
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens
+import Data.Binary as Binary
+import Data.Bytes.Serial
+import Data.Serialize as Cereal
+import Data.Data
+import Data.Distributive
+import Data.Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
+import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
+import Data.Semigroup.Foldable
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import Linear.V
+import Foreign.Storable (Storable)
+import GHC.Arr (Ix(..))
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
+import Linear.Metric
+import Linear.Epsilon
+import Linear.Vector
+import Prelude hiding (sum)
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
+#if !(MIN_VERSION_base(4,11,0))
+import Data.Semigroup
+#endif
+
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
+
+-- $setup
+-- >>> import Control.Applicative
+-- >>> import Control.Lens
+-- >>> import qualified Data.Foldable as F
+-- >>> let sum xs = F.sum xs
+
+-- | A 1-dimensional vector
+--
+-- >>> pure 1 :: V1 Int
+-- V1 1
+--
+-- >>> V1 2 + V1 3
+-- V1 5
+--
+-- >>> V1 2 * V1 3
+-- V1 6
+--
+-- >>> sum (V1 2)
+-- 2
+
+--data V2 a = V2 !a !a deriving (Eq,Ord,Show,Read,Data)
+newtype V1 a = V1 a
+  deriving (Eq,Ord,Show,Read,Data,
+            Functor,Traversable,
+            Epsilon,Storable,NFData
+           ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+           ,Lift
+#endif
+           )
+
+instance Foldable V1 where
+  foldMap f (V1 a) = f a
+#if MIN_VERSION_base(4,13,0)
+  foldMap' f (V1 a) = f a
+#endif
+  null _ = False
+  length _ = 1
+
+instance Finite V1 where
+  type Size V1 = 1
+  toV (V1 a) = V (V.singleton a)
+  fromV (V v) = V1 (v V.! 0)
+
+instance Foldable1 V1 where
+  foldMap1 f (V1 a) = f a
+  {-# INLINE foldMap1 #-}
+
+instance Traversable1 V1 where
+  traverse1 f (V1 a) = V1 <$> f a
+  {-# INLINE traverse1 #-}
+
+instance Apply V1 where
+  V1 f <.> V1 x = V1 (f x)
+  {-# INLINE (<.>) #-}
+
+instance Applicative V1 where
+  pure = V1
+  {-# INLINE pure #-}
+  V1 f <*> V1 x = V1 (f x)
+  {-# INLINE (<*>) #-}
+
+instance Additive V1 where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
+
+instance Bind V1 where
+  V1 a >>- f = f a
+  {-# INLINE (>>-) #-}
+
+instance Monad V1 where
+#if !(MIN_VERSION_base(4,11,0))
+  return = V1
+  {-# INLINE return #-}
+#endif
+  V1 a >>= f = f a
+  {-# INLINE (>>=) #-}
+
+instance Num a => Num (V1 a) where
+  (+) = liftA2 (+)
+  {-# INLINE (+) #-}
+  (-) = liftA2 (-)
+  {-# INLINE (-) #-}
+  (*) = liftA2 (*)
+  {-# INLINE (*) #-}
+  negate = fmap negate
+  {-# INLINE negate #-}
+  abs = fmap abs
+  {-# INLINE abs #-}
+  signum = fmap signum
+  {-# INLINE signum #-}
+  fromInteger = pure . fromInteger
+  {-# INLINE fromInteger #-}
+
+instance Fractional a => Fractional (V1 a) where
+  recip = fmap recip
+  {-# INLINE recip #-}
+  (/) = liftA2 (/)
+  {-# INLINE (/) #-}
+  fromRational = pure . fromRational
+  {-# INLINE fromRational #-}
+
+instance Floating a => Floating (V1 a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    (**) = liftA2 (**)
+    {-# INLINE (**) #-}
+    logBase = liftA2 logBase
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
+instance Hashable a => Hashable (V1 a) where
+  hash (V1 a) = hash a
+  hashWithSalt s (V1 a) = s `hashWithSalt` a
+
+instance Hashable1 V1 where
+  liftHashWithSalt h s (V1 a) = h s a
+  {-# INLINE liftHashWithSalt #-}
+
+instance Metric V1 where
+  dot (V1 a) (V1 b) = a * b
+  {-# INLINE dot #-}
+
+-- | A space that has at least 1 basis vector '_x'.
+class R1 t where
+  -- |
+  -- >>> V1 2 ^._x
+  -- 2
+  --
+  -- >>> V1 2 & _x .~ 3
+  -- V1 3
+  --
+  _x :: Lens' (t a) a
+
+ex :: R1 t => E t
+ex = E _x
+
+instance R1 V1 where
+  _x f (V1 a) = V1 <$> f a
+  {-# INLINE _x #-}
+
+instance R1 Identity where
+  _x f (Identity a) = Identity <$> f a
+  {-# INLINE _x #-}
+
+instance Distributive V1 where
+  distribute f = V1 (fmap (\(V1 x) -> x) f)
+  {-# INLINE distribute #-}
+
+instance Ix a => Ix (V1 a) where
+  {-# SPECIALISE instance Ix (V1 Int) #-}
+
+  range (V1 l1, V1 u1) =
+    [ V1 i1 | i1 <- range (l1,u1) ]
+  {-# INLINE range #-}
+
+  unsafeIndex (V1 l1,V1 u1) (V1 i1) = unsafeIndex (l1,u1) i1
+  {-# INLINE unsafeIndex #-}
+
+  inRange (V1 l1,V1 u1) (V1 i1) = inRange (l1,u1) i1
+  {-# INLINE inRange #-}
+
+instance Representable V1 where
+  type Rep V1 = E V1
+  tabulate f = V1 (f ex)
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
+
+instance WithIndex.FunctorWithIndex (E V1) V1 where
+  imap f (V1 a) = V1 (f ex a)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E V1) V1 where
+  ifoldMap f (V1 a) = f ex a
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E V1) V1 where
+  itraverse f (V1 a) = V1 <$> f ex a
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E V1) V1 where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E V1) V1 where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E V1) V1 where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (V1 a) = E V1
+type instance IxValue (V1 a) = a
+
+instance Ixed (V1 a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (V1 a) (V1 b) a b where
+  each f (V1 x) = V1 <$> f x
+  {-# INLINE each #-}
+
+newtype instance U.Vector    (V1 a) = V_V1  (U.Vector    a)
+newtype instance U.MVector s (V1 a) = MV_V1 (U.MVector s a)
+instance U.Unbox a => U.Unbox (V1 a)
+
+instance U.Unbox a => M.MVector U.MVector (V1 a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_V1 v) = M.basicLength v
+  basicUnsafeSlice m n (MV_V1 v) = MV_V1 (M.basicUnsafeSlice m n v)
+  basicOverlaps (MV_V1 v) (MV_V1 u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM MV_V1 (M.basicUnsafeNew n)
+  basicUnsafeRead (MV_V1 v) i = liftM V1 (M.basicUnsafeRead v i)
+  basicUnsafeWrite (MV_V1 v) i (V1 x) = M.basicUnsafeWrite v i x
+  basicInitialize (MV_V1 v) = M.basicInitialize v
+  {-# INLINE basicInitialize #-}
+
+instance U.Unbox a => G.Vector U.Vector (V1 a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_V1 v) = liftM V_V1 (G.basicUnsafeFreeze v)
+  basicUnsafeThaw (V_V1 v) = liftM MV_V1 (G.basicUnsafeThaw v)
+  basicLength (V_V1 v) = G.basicLength v
+  basicUnsafeSlice m n (V_V1 v) = V_V1 (G.basicUnsafeSlice m n v)
+  basicUnsafeIndexM (V_V1 v) i = liftM V1 (G.basicUnsafeIndexM v i)
+
+instance MonadZip V1 where
+  mzip (V1 a) (V1 b) = V1 (a, b)
+  mzipWith f (V1 a) (V1 b) = V1 (f a b)
+  munzip (V1 (a,b)) = (V1 a, V1 b)
+
+instance MonadFix V1 where
+  mfix f = V1 (let V1 a = f a in a)
+
+instance Bounded a => Bounded (V1 a) where
+  minBound = pure minBound
+  {-# INLINE minBound #-}
+  maxBound = pure maxBound
+  {-# INLINE maxBound #-}
+
+instance Serial1 V1 where
+  serializeWith f (V1 a) = f a
+  deserializeWith m = V1 `liftM` m
+
+instance Serial a => Serial (V1 a) where
+  serialize (V1 a) = serialize a
+  deserialize = V1 `liftM` deserialize
+
+instance Binary a => Binary (V1 a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (V1 a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Random a => Random (V1 a) where
+  random g = case random g of (a, g') -> (V1 a, g')
+  randoms g = V1 <$> randoms g
+  randomR (V1 a, V1 b) g = case randomR (a, b) g of (a', g') -> (V1 a', g')
+  randomRs (V1 a, V1 b) g = V1 <$> randomRs (a, b) g
+
+instance Uniform a => Uniform (V1 a) where
+
+instance UniformRange a => UniformRange (V1 a) where
+  uniformRM (V1 a, V1 b) g = V1 <$> uniformRM (a, b) g
+
+instance Eq1 V1 where
+  liftEq f (V1 a) (V1 b) = f a b
+instance Ord1 V1 where
+  liftCompare f (V1 a) (V1 b) = f a b
+instance Show1 V1 where
+  liftShowsPrec f _ d (V1 a) = showParen (d >= 10) $ showString "V1 " . f d a
+instance Read1 V1 where
+  liftReadsPrec f _ = readsData $ readsUnaryWith f "V1" V1
+
+instance Field1 (V1 a) (V1 b) a b where
+  _1 f (V1 x) = V1 <$> f x
+
+instance Semigroup a => Semigroup (V1 a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (V1 a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
+
diff --git a/src/Linear/V2.hs b/src/Linear/V2.hs
--- a/src/Linear/V2.hs
+++ b/src/Linear/V2.hs
@@ -1,11 +1,18 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE ScopedTypeVariables #-}
--- {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.V2
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -16,30 +23,63 @@
 ----------------------------------------------------------------------------
 module Linear.V2
   ( V2(..)
+  , R1(..)
   , R2(..)
+  , _yx
+  , ex, ey
   , perp
+  , angle
+  , unangle
+  , crossZ
   ) where
 
 import Control.Applicative
+import Control.DeepSeq (NFData(rnf))
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens hiding ((<.>))
+import Data.Binary as Binary
+import Data.Bytes.Serial
 import Data.Data
 import Data.Distributive
 import Data.Foldable
-import Data.Traversable
+import qualified Data.Foldable.WithIndex as WithIndex
+import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
 import Data.Semigroup
 import Data.Semigroup.Foldable
-import Data.Semigroup.Traversable
-import Data.Functor.Bind
+import Data.Serialize as Cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
 import Foreign.Ptr (castPtr)
 import Foreign.Storable (Storable(..))
 import GHC.Arr (Ix(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Linear.Metric
 import Linear.Epsilon
+import Linear.V
 import Linear.Vector
+import Linear.V1 (R1(..),ex)
 import Prelude hiding (sum)
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 
 -- $setup
+-- >>> import Control.Applicative
 -- >>> import Control.Lens
+-- >>> import qualified Data.Foldable as F
+-- >>> let sum xs = F.sum xs
 
 -- | A 2-dimensional vector
 --
@@ -55,8 +95,34 @@
 -- >>> sum (V2 1 2)
 -- 3
 
-data V2 a = V2 a a deriving (Eq,Ord,Show,Read,Data,Typeable)
+data V2 a = V2 !a !a deriving
+  (Eq,Ord,Show,Read,Data
+  ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+  ,Lift
+#endif
+  )
 
+instance Finite V2 where
+  type Size V2 = 2
+  toV (V2 a b) = V (V.fromListN 2 [a,b])
+  fromV (V v) = V2 (v V.! 0) (v V.! 1)
+
+instance Random a => Random (V2 a) where
+  random g = case random g of
+   (a, g') -> case random g' of
+     (b, g'') -> (V2 a b, g'')
+  {-# inline random #-}
+  randomR (V2 a b, V2 c d) g = case randomR (a, c) g of
+    (x, g') -> case randomR (b, d) g' of
+      (y, g'') -> (V2 x y, g'')
+  {-# inline randomR #-}
+
+instance Uniform a => Uniform (V2 a) where
+
+instance UniformRange a => UniformRange (V2 a) where
+  uniformRM (V2 a b, V2 c d) g = V2 <$> uniformRM (a, c) g <*> uniformRM (b, d) g
+
 instance Functor V2 where
   fmap f (V2 a b) = V2 (f a) (f b)
   {-# INLINE fmap #-}
@@ -66,6 +132,12 @@
 instance Foldable V2 where
   foldMap f (V2 a b) = f a `mappend` f b
   {-# INLINE foldMap #-}
+#if MIN_VERSION_base(4,13,0)
+  foldMap' f (V2 a b) = f a `mappend` f b
+  {-# INLINE foldMap' #-}
+#endif
+  null _ = False
+  length _ = 2
 
 instance Traversable V2 where
   traverse f (V2 a b) = V2 <$> f a <*> f b
@@ -81,16 +153,30 @@
 
 instance Apply V2 where
   V2 a b <.> V2 d e = V2 (a d) (b e)
-  {-@ INLINE (<.>) #-}
+  {-# INLINE (<.>) #-}
 
 instance Applicative V2 where
   pure a = V2 a a
   {-# INLINE pure #-}
   V2 a b <*> V2 d e = V2 (a d) (b e)
-  {-@ INLINE (<*>) #-}
+  {-# INLINE (<*>) #-}
 
-instance Additive V2
+instance Hashable a => Hashable (V2 a) where
+  hashWithSalt s (V2 a b) = s `hashWithSalt` a `hashWithSalt` b
+  {-# INLINE hashWithSalt #-}
 
+instance Hashable1 V2 where
+  liftHashWithSalt h s (V2 a b) = s `h` a `h` b
+  {-# INLINE liftHashWithSalt #-}
+
+instance Additive V2 where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
+
 instance Bind V2 where
   V2 a b >>- f = V2 a' b' where
     V2 a' _ = f a
@@ -98,8 +184,10 @@
   {-# INLINE (>>-) #-}
 
 instance Monad V2 where
+#if !(MIN_VERSION_base(4,11,0))
   return a = V2 a a
   {-# INLINE return #-}
+#endif
   V2 a b >>= f = V2 a' b' where
     V2 a' _ = f a
     V2 _ b' = f b
@@ -129,26 +217,50 @@
   fromRational = pure . fromRational
   {-# INLINE fromRational #-}
 
+instance Floating a => Floating (V2 a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    (**) = liftA2 (**)
+    {-# INLINE (**) #-}
+    logBase = liftA2 logBase
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
 instance Metric V2 where
   dot (V2 a b) (V2 c d) = a * c + b * d
   {-# INLINE dot #-}
 
 -- | A space that distinguishes 2 orthogonal basis vectors '_x' and '_y', but may have more.
-class R2 t where
-  -- |
-  -- >>> V2 1 2 ^._x
-  -- 1
-  --
-  -- >>> V2 1 2 & _x .~ 3
-  -- V2 3 2
-  --
-  -- @
-  -- '_x' :: Lens' (t a) a
-  -- @
-  _x :: Functor f => (a -> f a) -> t a -> f (t a)
-  _x = _xy._x
-  {-# INLINE _x #-}
-
+class R1 t => R2 t where
   -- |
   -- >>> V2 1 2 ^._y
   -- 2
@@ -156,31 +268,32 @@
   -- >>> V2 1 2 & _y .~ 3
   -- V2 1 3
   --
-  -- @
-  -- '_y' :: Lens' (t a) a
-  -- @
-  _y :: Functor f => (a -> f a) -> t a -> f (t a)
+  _y :: Lens' (t a) a
   _y = _xy._y
   {-# INLINE _y #-}
 
-  -- |
-  -- @
-  -- '_xy' :: Lens' (t a) ('V2' a)
-  -- @
-  _xy :: Functor f => (V2 a -> f (V2 a)) -> t a -> f (t a)
+  _xy :: Lens' (t a) (V2 a)
 
-instance R2 V2 where
+-- |
+-- >>> V2 1 2 ^. _yx
+-- V2 2 1
+_yx :: R2 t => Lens' (t a) (V2 a)
+_yx f = _xy $ \(V2 a b) -> f (V2 b a) <&> \(V2 b' a') -> V2 a' b'
+{-# INLINE _yx #-}
+
+ey :: R2 t => E t
+ey = E _y
+
+instance R1 V2 where
   _x f (V2 a b) = (`V2` b) <$> f a
   {-# INLINE _x #-}
+
+instance R2 V2 where
   _y f (V2 a b) = V2 a <$> f b
   {-# INLINE _y #-}
   _xy = id
   {-# INLINE _xy #-}
 
-instance Core V2 where
-  core f = V2 (f _x) (f _y)
-  {-# INLINE core #-}
-
 instance Distributive V2 where
   distribute f = V2 (fmap (\(V2 x _) -> x) f) (fmap (\(V2 _ y) -> y) f)
   {-# INLINE distribute #-}
@@ -223,3 +336,156 @@
   inRange (V2 l1 l2,V2 u1 u2) (V2 i1 i2) =
     inRange (l1,u1) i1 && inRange (l2,u2) i2
   {-# INLINE inRange #-}
+
+instance Representable V2 where
+  type Rep V2 = E V2
+  tabulate f = V2 (f ex) (f ey)
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
+
+instance WithIndex.FunctorWithIndex (E V2) V2 where
+  imap f (V2 a b) = V2 (f ex a) (f ey b)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E V2) V2 where
+  ifoldMap f (V2 a b) = f ex a `mappend` f ey b
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E V2) V2 where
+  itraverse f (V2 a b) = V2 <$> f ex a <*> f ey b
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E V2) V2 where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E V2) V2 where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E V2) V2 where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (V2 a) = E V2
+type instance IxValue (V2 a) = a
+
+instance Ixed (V2 a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (V2 a) (V2 b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+data instance U.Vector    (V2 a) =  V_V2 {-# UNPACK #-} !Int !(U.Vector    a)
+data instance U.MVector s (V2 a) = MV_V2 {-# UNPACK #-} !Int !(U.MVector s a)
+instance U.Unbox a => U.Unbox (V2 a)
+
+instance U.Unbox a => M.MVector U.MVector (V2 a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_V2 n _) = n
+  basicUnsafeSlice m n (MV_V2 _ v) = MV_V2 n (M.basicUnsafeSlice (2*m) (2*n) v)
+  basicOverlaps (MV_V2 _ v) (MV_V2 _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_V2 n) (M.basicUnsafeNew (2*n))
+  basicUnsafeRead (MV_V2 _ v) i =
+    do let o = 2*i
+       x <- M.basicUnsafeRead v o
+       y <- M.basicUnsafeRead v (o+1)
+       return (V2 x y)
+  basicUnsafeWrite (MV_V2 _ v) i (V2 x y) =
+    do let o = 2*i
+       M.basicUnsafeWrite v o     x
+       M.basicUnsafeWrite v (o+1) y
+  basicInitialize (MV_V2 _ v) = M.basicInitialize v
+  {-# INLINE basicInitialize #-}
+
+instance U.Unbox a => G.Vector U.Vector (V2 a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_V2 n v) = liftM ( V_V2 n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_V2 n v) = liftM (MV_V2 n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_V2 n _) = n
+  basicUnsafeSlice m n (V_V2 _ v) = V_V2 n (G.basicUnsafeSlice (2*m) (2*n) v)
+  basicUnsafeIndexM (V_V2 _ v) i =
+    do let o = 2*i
+       x <- G.basicUnsafeIndexM v o
+       y <- G.basicUnsafeIndexM v (o+1)
+       return (V2 x y)
+
+instance MonadZip V2 where
+  mzipWith = liftA2
+
+instance MonadFix V2 where
+  mfix f = V2 (let V2 a _ = f a in a)
+              (let V2 _ a = f a in a)
+
+angle :: Floating a => a -> V2 a
+angle a = V2 (cos a) (sin a)
+
+unangle :: (Floating a, Ord a) => V2 a -> a
+unangle a@(V2 ax ay) =
+  let alpha = asin $ ay / norm a
+  in if ax < 0
+       then pi - alpha
+       else alpha
+
+-- | The Z-component of the cross product of two vectors in the XY-plane.
+--
+-- >>> crossZ (V2 1 0) (V2 0 1)
+-- 1
+crossZ :: Num a => V2 a -> V2 a -> a
+crossZ (V2 x1 y1) (V2 x2 y2) = x1*y2 - y1*x2
+{-# INLINE crossZ #-}
+
+instance Bounded a => Bounded (V2 a) where
+  minBound = pure minBound
+  {-# INLINE minBound #-}
+  maxBound = pure maxBound
+  {-# INLINE maxBound #-}
+
+instance NFData a => NFData (V2 a) where
+  rnf (V2 a b) = rnf a `seq` rnf b
+
+instance Serial1 V2 where
+  serializeWith = traverse_
+  deserializeWith k = V2 <$> k <*> k
+
+instance Serial a => Serial (V2 a) where
+  serialize = serializeWith serialize
+  deserialize = deserializeWith deserialize
+
+instance Binary a => Binary (V2 a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (V2 a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 V2 where
+  liftEq f (V2 a b) (V2 c d) = f a c && f b d
+instance Ord1 V2 where
+  liftCompare f (V2 a b) (V2 c d) = f a c `mappend` f b d
+instance Read1 V2 where
+  liftReadsPrec f _ = readsData $ readsBinaryWith f f "V2" V2
+instance Show1 V2 where
+  liftShowsPrec f _ d (V2 a b) = showsBinaryWith f f "V2" d a b
+
+instance Field1 (V2 a) (V2 a) a a where
+  _1 f (V2 x y) = f x <&> \x' -> V2 x' y
+
+instance Field2 (V2 a) (V2 a) a a where
+  _2 f (V2 x y) = f y <&> \y' -> V2 x y'
+
+instance Semigroup a => Semigroup (V2 a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (V2 a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
diff --git a/src/Linear/V3.hs b/src/Linear/V3.hs
--- a/src/Linear/V3.hs
+++ b/src/Linear/V3.hs
@@ -1,8 +1,18 @@
-{-# LANGUAGE DeriveDataTypeable, ScopedTypeVariables #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.V3
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -14,33 +24,76 @@
 module Linear.V3
   ( V3(..)
   , cross, triple
+  , R1(..)
   , R2(..)
+  , _yx
   , R3(..)
+  , _xz, _yz, _zx, _zy
+  , _xzy, _yxz, _yzx, _zxy, _zyx
+  , ex, ey, ez
   ) where
 
+#if !MIN_VERSION_base(4,18,0)
 import Control.Applicative
+#endif
+import Control.DeepSeq (NFData(rnf))
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens hiding ((<.>))
+import Data.Binary as Binary -- binary
+import Data.Bytes.Serial -- bytes
 import Data.Data
 import Data.Distributive
 import Data.Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
 import Data.Functor.Bind
-import Data.Traversable
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Semigroup
+#endif
 import Data.Semigroup.Foldable
-import Data.Semigroup.Traversable
+import Data.Serialize as Cereal -- cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Foreign.Ptr (castPtr)
 import Foreign.Storable (Storable(..))
 import GHC.Arr (Ix(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
 import Linear.Epsilon
 import Linear.Metric
+import Linear.V
 import Linear.V2
 import Linear.Vector
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 
-{-# ANN module "HLint: ignore Reduce duplication" #-}
+-- $setup
+-- >>> import Control.Lens hiding (index)
 
 -- | A 3-dimensional vector
-data V3 a = V3 a a a deriving (Eq,Ord,Show,Read,Data,Typeable)
+data V3 a = V3 !a !a !a deriving (Eq,Ord,Show,Read,Data
+                                 ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+                                 ,Lift
+#endif
+                                 )
 
+instance Finite V3 where
+  type Size V3 = 3
+  toV (V3 a b c) = V (V.fromListN 3 [a,b,c])
+  fromV (V v) = V3 (v V.! 0) (v V.! 1) (v V.! 2)
+
 instance Functor V3 where
   fmap f (V3 a b c) = V3 (f a) (f b) (f c)
   {-# INLINE fmap #-}
@@ -50,7 +103,31 @@
 instance Foldable V3 where
   foldMap f (V3 a b c) = f a `mappend` f b `mappend` f c
   {-# INLINE foldMap #-}
+#if MIN_VERSION_base(4,13,0)
+  foldMap' f (V3 a b c) = (f a `mappend` f b) `mappend` f c
+  {-# INLINE foldMap' #-}
+#endif
+  null _ = False
+  length _ = 3
 
+instance Random a => Random (V3 a) where
+  random g = case random g of
+    (a, g') -> case random g' of
+      (b, g'') -> case random g'' of
+        (c, g''') -> (V3 a b c, g''')
+  randomR (V3 a b c, V3 a' b' c') g = case randomR (a,a') g of
+    (a'', g') -> case randomR (b,b') g' of
+      (b'', g'') -> case randomR (c,c') g'' of
+        (c'', g''') -> (V3 a'' b'' c'', g''')
+
+instance Uniform a => Uniform (V3 a) where
+
+instance UniformRange a => UniformRange (V3 a) where
+  uniformRM (V3 a b c, V3 a' b' c') g = V3
+    <$> uniformRM (a, a') g
+    <*> uniformRM (b, b') g
+    <*> uniformRM (c, c') g
+
 instance Traversable V3 where
   traverse f (V3 a b c) = V3 <$> f a <*> f b <*> f c
   {-# INLINE traverse #-}
@@ -73,7 +150,13 @@
   V3 a b c <*> V3 d e f = V3 (a d) (b e) (c f)
   {-# INLINE (<*>) #-}
 
-instance Additive V3
+instance Additive V3 where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
 instance Bind V3 where
   V3 a b c >>- f = V3 a' b' c' where
@@ -83,8 +166,10 @@
   {-# INLINE (>>-) #-}
 
 instance Monad V3 where
+#if !(MIN_VERSION_base(4,11,0))
   return a = V3 a a a
   {-# INLINE return #-}
+#endif
   V3 a b c >>= f = V3 a' b' c' where
     V3 a' _ _ = f a
     V3 _ b' _ = f b
@@ -115,6 +200,52 @@
   fromRational = pure . fromRational
   {-# INLINE fromRational #-}
 
+instance Floating a => Floating (V3 a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    (**) = liftA2 (**)
+    {-# INLINE (**) #-}
+    logBase = liftA2 logBase
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
+instance Hashable a => Hashable (V3 a) where
+  hashWithSalt s (V3 a b c) = s `hashWithSalt` a `hashWithSalt` b `hashWithSalt` c
+  {-# INLINE hashWithSalt #-}
+
+instance Hashable1 V3 where
+  liftHashWithSalt h s (V3 a b c) = s `h` a `h` b `h` c
+  {-# INLINE liftHashWithSalt #-}
+
 instance Metric V3 where
   dot (V3 a b c) (V3 d e f) = a * d + b * e + c * f
   {-# INLINABLE dot #-}
@@ -126,19 +257,51 @@
 -- | A space that distinguishes 3 orthogonal basis vectors: '_x', '_y', and '_z'. (It may have more)
 class R2 t => R3 t where
   -- |
-  -- @
-  -- '_z' :: Lens' (t a) a
-  -- @
-  _z :: Functor f => (a -> f a) -> t a -> f (t a)
-  -- |
-  -- @
-  -- '_xyz' :: Lens' (t a) ('V3' a)
-  -- @
-  _xyz :: Functor f => (V3 a -> f (V3 a)) -> t a -> f (t a)
+  -- >>> V3 1 2 3 ^. _z
+  -- 3
+  _z :: Lens' (t a) a
 
-instance R2 V3 where
+  _xyz :: Lens' (t a) (V3 a)
+
+_xz, _yz, _zx, _zy :: R3 t => Lens' (t a) (V2 a)
+
+_xz f = _xyz $ \(V3 a b c) -> f (V2 a c) <&> \(V2 a' c') -> V3 a' b c'
+{-# INLINE _xz #-}
+
+_yz f = _xyz $ \(V3 a b c) -> f (V2 b c) <&> \(V2 b' c') -> V3 a b' c'
+{-# INLINE _yz #-}
+
+_zx f = _xyz $ \(V3 a b c) -> f (V2 c a) <&> \(V2 c' a') -> V3 a' b c'
+{-# INLINE _zx #-}
+
+_zy f = _xyz $ \(V3 a b c) -> f (V2 c b) <&> \(V2 c' b') -> V3 a b' c'
+{-# INLINE _zy #-}
+
+_xzy, _yxz, _yzx, _zxy, _zyx :: R3 t => Lens' (t a) (V3 a)
+
+_xzy f = _xyz $ \(V3 a b c) -> f (V3 a c b) <&> \(V3 a' c' b') -> V3 a' b' c'
+{-# INLINE _xzy #-}
+
+_yxz f = _xyz $ \(V3 a b c) -> f (V3 b a c) <&> \(V3 b' a' c') -> V3 a' b' c'
+{-# INLINE _yxz #-}
+
+_yzx f = _xyz $ \(V3 a b c) -> f (V3 b c a) <&> \(V3 b' c' a') -> V3 a' b' c'
+{-# INLINE _yzx #-}
+
+_zxy f = _xyz $ \(V3 a b c) -> f (V3 c a b) <&> \(V3 c' a' b') -> V3 a' b' c'
+{-# INLINE _zxy #-}
+
+_zyx f = _xyz $ \(V3 a b c) -> f (V3 c b a) <&> \(V3 c' b' a') -> V3 a' b' c'
+{-# INLINE _zyx #-}
+
+ez :: R3 t => E t
+ez = E _z
+
+instance R1 V3 where
   _x f (V3 a b c) = (\a' -> V3 a' b c) <$> f a
   {-# INLINE _x #-}
+
+instance R2 V3 where
   _y f (V3 a b c) = (\b' -> V3 a b' c) <$> f b
   {-# INLINE _y #-}
   _xy f (V3 a b c) = (\(V2 a' b') -> V3 a' b' c) <$> f (V2 a b)
@@ -150,10 +313,6 @@
   _xyz = id
   {-# INLINE _xyz #-}
 
-instance Core V3 where
-  core f = V3 (f _x) (f _y) (f _z)
-  {-# INLINE core #-}
-
 instance Storable a => Storable (V3 a) where
   sizeOf _ = 3 * sizeOf (undefined::a)
   {-# INLINE sizeOf #-}
@@ -202,3 +361,153 @@
     inRange (l1,u1) i1 && inRange (l2,u2) i2 &&
     inRange (l3,u3) i3
   {-# INLINE inRange #-}
+
+instance Representable V3 where
+  type Rep V3 = E V3
+  tabulate f = V3 (f ex) (f ey) (f ez)
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
+
+instance WithIndex.FunctorWithIndex (E V3) V3 where
+  imap f (V3 a b c) = V3 (f ex a) (f ey b) (f ez c)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E V3) V3 where
+  ifoldMap f (V3 a b c) = f ex a `mappend` f ey b `mappend` f ez c
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E V3) V3 where
+  itraverse f (V3 a b c) = V3 <$> f ex a <*> f ey b <*> f ez c
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E V3) V3 where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E V3) V3 where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E V3) V3 where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (V3 a) = E V3
+type instance IxValue (V3 a) = a
+
+instance Ixed (V3 a) where
+  ix i = el i
+  {-# INLINE ix #-}
+
+instance Each (V3 a) (V3 b) a b where
+  each = traverse
+  {-# INLINE each #-}
+
+data instance U.Vector    (V3 a) =  V_V3 {-# UNPACK #-} !Int !(U.Vector    a)
+data instance U.MVector s (V3 a) = MV_V3 {-# UNPACK #-} !Int !(U.MVector s a)
+instance U.Unbox a => U.Unbox (V3 a)
+
+instance U.Unbox a => M.MVector U.MVector (V3 a) where
+  {-# INLINE basicLength #-}
+  {-# INLINE basicUnsafeSlice #-}
+  {-# INLINE basicOverlaps #-}
+  {-# INLINE basicUnsafeNew #-}
+  {-# INLINE basicUnsafeRead #-}
+  {-# INLINE basicUnsafeWrite #-}
+  basicLength (MV_V3 n _) = n
+  basicUnsafeSlice m n (MV_V3 _ v) = MV_V3 n (M.basicUnsafeSlice (3*m) (3*n) v)
+  basicOverlaps (MV_V3 _ v) (MV_V3 _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_V3 n) (M.basicUnsafeNew (3*n))
+  basicUnsafeRead (MV_V3 _ v) i =
+    do let o = 3*i
+       x <- M.basicUnsafeRead v o
+       y <- M.basicUnsafeRead v (o+1)
+       z <- M.basicUnsafeRead v (o+2)
+       return (V3 x y z)
+  basicUnsafeWrite (MV_V3 _ v) i (V3 x y z) =
+    do let o = 3*i
+       M.basicUnsafeWrite v o     x
+       M.basicUnsafeWrite v (o+1) y
+       M.basicUnsafeWrite v (o+2) z
+  basicInitialize (MV_V3 _ v) = M.basicInitialize v
+  {-# INLINE basicInitialize #-}
+
+instance U.Unbox a => G.Vector U.Vector (V3 a) where
+  {-# INLINE basicUnsafeFreeze #-}
+  {-# INLINE basicUnsafeThaw   #-}
+  {-# INLINE basicLength       #-}
+  {-# INLINE basicUnsafeSlice  #-}
+  {-# INLINE basicUnsafeIndexM #-}
+  basicUnsafeFreeze (MV_V3 n v) = liftM ( V_V3 n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_V3 n v) = liftM (MV_V3 n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_V3 n _) = n
+  basicUnsafeSlice m n (V_V3 _ v) = V_V3 n (G.basicUnsafeSlice (3*m) (3*n) v)
+  basicUnsafeIndexM (V_V3 _ v) i =
+    do let o = 3*i
+       x <- G.basicUnsafeIndexM v o
+       y <- G.basicUnsafeIndexM v (o+1)
+       z <- G.basicUnsafeIndexM v (o+2)
+       return (V3 x y z)
+
+instance MonadZip V3 where
+  mzipWith = liftA2
+
+instance MonadFix V3 where
+  mfix f = V3 (let V3 a _ _ = f a in a)
+              (let V3 _ a _ = f a in a)
+              (let V3 _ _ a = f a in a)
+
+instance Bounded a => Bounded (V3 a) where
+  minBound = pure minBound
+  {-# INLINE minBound #-}
+  maxBound = pure maxBound
+  {-# INLINE maxBound #-}
+
+instance NFData a => NFData (V3 a) where
+  rnf (V3 a b c) = rnf a `seq` rnf b `seq` rnf c
+
+instance Serial1 V3 where
+  serializeWith = traverse_
+  deserializeWith k = V3 <$> k <*> k <*> k
+
+instance Serial a => Serial (V3 a) where
+  serialize = serializeWith serialize
+  deserialize = deserializeWith deserialize
+
+instance Binary a => Binary (V3 a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (V3 a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 V3 where
+  liftEq k (V3 a b c) (V3 d e f) = k a d && k b e && k c f
+instance Ord1 V3 where
+  liftCompare k (V3 a b c) (V3 d e f) = k a d `mappend` k b e `mappend` k c f
+instance Read1 V3 where
+  liftReadsPrec k _ d = readParen (d > 10) $ \r ->
+     [ (V3 a b c, r4)
+     | ("V3",r1) <- lex r
+     , (a,r2) <- k 11 r1
+     , (b,r3) <- k 11 r2
+     , (c,r4) <- k 11 r3
+     ]
+instance Show1 V3 where
+  liftShowsPrec f _ d (V3 a b c) = showParen (d > 10) $
+     showString "V3 " . f 11 a . showChar ' ' . f 11 b . showChar ' ' . f 11 c
+
+instance Field1 (V3 a) (V3 a) a a where
+  _1 f (V3 x y z) = f x <&> \x' -> V3 x' y z
+
+instance Field2 (V3 a) (V3 a) a a where
+  _2 f (V3 x y z) = f y <&> \y' -> V3 x y' z
+
+instance Field3 (V3 a) (V3 a) a a where
+  _3 f (V3 x y z) = f z <&> \z' -> V3 x y z'
+
+instance Semigroup a => Semigroup (V3 a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (V3 a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
+
diff --git a/src/Linear/V4.hs b/src/Linear/V4.hs
--- a/src/Linear/V4.hs
+++ b/src/Linear/V4.hs
@@ -1,8 +1,18 @@
-{-# LANGUAGE DeriveDataTypeable, ScopedTypeVariables #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveLift #-}
+
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.V4
--- Copyright   :  (C) 2012-2013 Edward Kmett,
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
@@ -13,36 +23,85 @@
 ----------------------------------------------------------------------------
 module Linear.V4
   ( V4(..)
-  , vector, point
+  , vector, point, normalizePoint
+  , R1(..)
   , R2(..)
+  , _yx
   , R3(..)
+  , _xz, _yz, _zx, _zy
+  , _xzy, _yxz, _yzx, _zxy, _zyx
   , R4(..)
+  , _xw, _yw, _zw, _wx, _wy, _wz
+  , _xyw, _xzw, _xwy, _xwz, _yxw, _yzw, _ywx, _ywz, _zxw, _zyw, _zwx, _zwy
+  , _wxy, _wxz, _wyx, _wyz, _wzx, _wzy
+  , _xywz, _xzyw, _xzwy, _xwyz, _xwzy, _yxzw , _yxwz, _yzxw, _yzwx, _ywxz
+  , _ywzx, _zxyw, _zxwy, _zyxw, _zywx, _zwxy, _zwyx, _wxyz, _wxzy, _wyxz
+  , _wyzx, _wzxy, _wzyx
+  , ex, ey, ez, ew
   ) where
 
+#if !MIN_VERSION_base(4,18,0)
 import Control.Applicative
+#endif
+import Control.DeepSeq (NFData(rnf))
+import Control.Monad (liftM)
+import Control.Monad.Fix
+import Control.Monad.Zip
+import Control.Lens as Lens hiding ((<.>))
+import Data.Binary as Binary
+import Data.Bytes.Serial
 import Data.Data
 import Data.Distributive
 import Data.Foldable
+import qualified Data.Foldable.WithIndex as WithIndex
 import Data.Functor.Bind
+import Data.Functor.Classes
+import Data.Functor.Rep
+import qualified Data.Functor.WithIndex as WithIndex
+import Data.Hashable
+import Data.Hashable.Lifted
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Semigroup
+#endif
 import Data.Semigroup.Foldable
-import Data.Semigroup.Traversable
-import Data.Traversable
+import Data.Serialize as Cereal
+import qualified Data.Traversable.WithIndex as WithIndex
+import qualified Data.Vector as V
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Unboxed.Base as U
 import Foreign.Ptr (castPtr)
 import Foreign.Storable (Storable(..))
 import GHC.Arr (Ix(..))
-import Linear.Core
+import GHC.Generics (Generic, Generic1)
+#if defined(MIN_VERSION_template_haskell)
+import Language.Haskell.TH.Syntax (Lift)
+#endif
 import Linear.Epsilon
 import Linear.Metric
+import Linear.V
 import Linear.V2
 import Linear.V3
 import Linear.Vector
+import System.Random (Random(..), Uniform)
+import System.Random.Stateful (UniformRange(..))
 
-{-# ANN module "HLint: ignore Reduce duplication" #-}
+-- $setup
+-- >>> import Control.Lens hiding (index)
 
 -- | A 4-dimensional vector.
-data V4 a = V4 a a a a deriving (Eq,Ord,Show,Read,Data,Typeable)
+data V4 a = V4 !a !a !a !a deriving (Eq,Ord,Show,Read,Data
+                                    ,Generic,Generic1
+#if defined(MIN_VERSION_template_haskell)
+                                    ,Lift
+#endif
+                                    )
 
+instance Finite V4 where
+  type Size V4 = 4
+  toV (V4 a b c d) = V (V.fromListN 4 [a,b,c,d])
+  fromV (V v) = V4 (v V.! 0) (v V.! 1) (v V.! 2) (v V.! 3)
+
 instance Functor V4 where
   fmap f (V4 a b c d) = V4 (f a) (f b) (f c) (f d)
   {-# INLINE fmap #-}
@@ -52,7 +111,34 @@
 instance Foldable V4 where
   foldMap f (V4 a b c d) = f a `mappend` f b `mappend` f c `mappend` f d
   {-# INLINE foldMap #-}
+#if MIN_VERSION_base(4,13,0)
+  foldMap' f (V4 a b c d) = ((f a `mappend` f b) `mappend` f c) `mappend` f d
+  {-# INLINE foldMap' #-}
+#endif
+  null _ = False
+  length _ = 4
 
+instance Random a => Random (V4 a) where
+  random g = case random g of
+    (a, g') -> case random g' of
+      (b, g'') -> case random g'' of
+        (c, g''') -> case random g''' of
+          (d, g'''') -> (V4 a b c d, g'''')
+  randomR (V4 a b c d, V4 a' b' c' d') g = case randomR (a,a') g of
+    (a'', g') -> case randomR (b,b') g' of
+      (b'', g'') -> case randomR (c,c') g'' of
+        (c'', g''') -> case randomR (d,d') g''' of
+          (d'', g'''') -> (V4 a'' b'' c'' d'', g'''')
+
+instance Uniform a => Uniform (V4 a) where
+
+instance UniformRange a => UniformRange (V4 a) where
+  uniformRM (V4 a b c d, V4 a' b' c' d') g = V4
+    <$> uniformRM (a, a') g
+    <*> uniformRM (b, b') g
+    <*> uniformRM (c, c') g
+    <*> uniformRM (d, d') g
+
 instance Traversable V4 where
   traverse f (V4 a b c d) = V4 <$> f a <*> f b <*> f c <*> f d
   {-# INLINE traverse #-}
@@ -75,7 +161,13 @@
   V4 a b c d <.> V4 e f g h = V4 (a e) (b f) (c g) (d h)
   {-# INLINE (<.>) #-}
 
-instance Additive V4
+instance Additive V4 where
+  zero = pure 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
 instance Bind V4 where
   V4 a b c d >>- f = V4 a' b' c' d' where
@@ -86,8 +178,10 @@
   {-# INLINE (>>-) #-}
 
 instance Monad V4 where
+#if !(MIN_VERSION_base(4,11,0))
   return a = V4 a a a a
   {-# INLINE return #-}
+#endif
   V4 a b c d >>= f = V4 a' b' c' d' where
     V4 a' _ _ _ = f a
     V4 _ b' _ _ = f b
@@ -119,6 +213,44 @@
   fromRational = pure . fromRational
   {-# INLINE fromRational #-}
 
+instance Floating a => Floating (V4 a) where
+    pi = pure pi
+    {-# INLINE pi #-}
+    exp = fmap exp
+    {-# INLINE exp #-}
+    sqrt = fmap sqrt
+    {-# INLINE sqrt #-}
+    log = fmap log
+    {-# INLINE log #-}
+    (**) = liftA2 (**)
+    {-# INLINE (**) #-}
+    logBase = liftA2 logBase
+    {-# INLINE logBase #-}
+    sin = fmap sin
+    {-# INLINE sin #-}
+    tan = fmap tan
+    {-# INLINE tan #-}
+    cos = fmap cos
+    {-# INLINE cos #-}
+    asin = fmap asin
+    {-# INLINE asin #-}
+    atan = fmap atan
+    {-# INLINE atan #-}
+    acos = fmap acos
+    {-# INLINE acos #-}
+    sinh = fmap sinh
+    {-# INLINE sinh #-}
+    tanh = fmap tanh
+    {-# INLINE tanh #-}
+    cosh = fmap cosh
+    {-# INLINE cosh #-}
+    asinh = fmap asinh
+    {-# INLINE asinh #-}
+    atanh = fmap atanh
+    {-# INLINE atanh #-}
+    acosh = fmap acosh
+    {-# INLINE acosh #-}
+
 instance Metric V4 where
   dot (V4 a b c d) (V4 e f g h) = a * e + b * f + c * g + d * h
   {-# INLINE dot #-}
@@ -130,22 +262,176 @@
                     (fmap (\(V4 _ _ _ w) -> w) f)
   {-# INLINE distribute #-}
 
+instance Hashable a => Hashable (V4 a) where
+  hashWithSalt s (V4 a b c d) = s `hashWithSalt` a `hashWithSalt` b `hashWithSalt` c `hashWithSalt` d
+  {-# INLINE hashWithSalt #-}
+
+instance Hashable1 V4 where
+  liftHashWithSalt h s (V4 a b c d) = s `h` a `h` b `h` c `h` d
+  {-# INLINE liftHashWithSalt #-}
+
 -- | A space that distinguishes orthogonal basis vectors '_x', '_y', '_z', '_w'. (It may have more.)
 class R3 t => R4 t where
   -- |
-  -- @
-  -- '_w' :: Lens' (t a) a
-  -- @
-  _w :: Functor f => (a -> f a) -> t a -> f (t a)
-  -- |
-  -- @
-  -- '_xyzw' :: Lens' (t a) ('V4' a)
-  -- @
-  _xyzw :: Functor f => (V4 a -> f (V4 a)) -> t a -> f (t a)
+  -- >>> V4 1 2 3 4 ^._w
+  -- 4
+  _w :: Lens' (t a) a
+  _xyzw :: Lens' (t a) (V4 a)
 
-instance R2 V4 where
+_xw, _yw, _zw, _wx, _wy, _wz :: R4 t => Lens' (t a) (V2 a)
+_xw f = _xyzw $ \(V4 a b c d) -> f (V2 a d) <&> \(V2 a' d') -> V4 a' b c d'
+{-# INLINE _xw #-}
+
+_yw f = _xyzw $ \(V4 a b c d) -> f (V2 b d) <&> \(V2 b' d') -> V4 a b' c d'
+{-# INLINE _yw #-}
+
+_zw f = _xyzw $ \(V4 a b c d) -> f (V2 c d) <&> \(V2 c' d') -> V4 a b c' d'
+{-# INLINE _zw #-}
+
+_wx f = _xyzw $ \(V4 a b c d) -> f (V2 d a) <&> \(V2 d' a') -> V4 a' b c d'
+{-# INLINE _wx #-}
+
+_wy f = _xyzw $ \(V4 a b c d) -> f (V2 d b) <&> \(V2 d' b') -> V4 a b' c d'
+{-# INLINE _wy #-}
+
+_wz f = _xyzw $ \(V4 a b c d) -> f (V2 d c) <&> \(V2 d' c') -> V4 a b c' d'
+{-# INLINE _wz #-}
+
+_xyw, _xzw, _xwy, _xwz, _yxw, _yzw, _ywx, _ywz, _zxw, _zyw, _zwx, _zwy, _wxy, _wxz, _wyx, _wyz, _wzx, _wzy :: R4 t => Lens' (t a) (V3 a)
+_xyw f = _xyzw $ \(V4 a b c d) -> f (V3 a b d) <&> \(V3 a' b' d') -> V4 a' b' c d'
+{-# INLINE _xyw #-}
+
+_xzw f = _xyzw $ \(V4 a b c d) -> f (V3 a c d) <&> \(V3 a' c' d') -> V4 a' b c' d'
+{-# INLINE _xzw #-}
+
+_xwy f = _xyzw $ \(V4 a b c d) -> f (V3 a d b) <&> \(V3 a' d' b') -> V4 a' b' c d'
+{-# INLINE _xwy #-}
+
+_xwz f = _xyzw $ \(V4 a b c d) -> f (V3 a d c) <&> \(V3 a' d' c') -> V4 a' b c' d'
+{-# INLINE _xwz #-}
+
+_yxw f = _xyzw $ \(V4 a b c d) -> f (V3 b a d) <&> \(V3 b' a' d') -> V4 a' b' c d'
+{-# INLINE _yxw #-}
+
+_yzw f = _xyzw $ \(V4 a b c d) -> f (V3 b c d) <&> \(V3 b' c' d') -> V4 a b' c' d'
+{-# INLINE _yzw #-}
+
+_ywx f = _xyzw $ \(V4 a b c d) -> f (V3 b d a) <&> \(V3 b' d' a') -> V4 a' b' c d'
+{-# INLINE _ywx #-}
+
+_ywz f = _xyzw $ \(V4 a b c d) -> f (V3 b d c) <&> \(V3 b' d' c') -> V4 a b' c' d'
+{-# INLINE _ywz #-}
+
+_zxw f = _xyzw $ \(V4 a b c d) -> f (V3 c a d) <&> \(V3 c' a' d') -> V4 a' b c' d'
+{-# INLINE _zxw #-}
+
+_zyw f = _xyzw $ \(V4 a b c d) -> f (V3 c b d) <&> \(V3 c' b' d') -> V4 a b' c' d'
+{-# INLINE _zyw #-}
+
+_zwx f = _xyzw $ \(V4 a b c d) -> f (V3 c d a) <&> \(V3 c' d' a') -> V4 a' b c' d'
+{-# INLINE _zwx #-}
+
+_zwy f = _xyzw $ \(V4 a b c d) -> f (V3 c d b) <&> \(V3 c' d' b') -> V4 a b' c' d'
+{-# INLINE _zwy #-}
+
+_wxy f = _xyzw $ \(V4 a b c d) -> f (V3 d a b) <&> \(V3 d' a' b') -> V4 a' b' c d'
+{-# INLINE _wxy #-}
+
+_wxz f = _xyzw $ \(V4 a b c d) -> f (V3 d a c) <&> \(V3 d' a' c') -> V4 a' b c' d'
+{-# INLINE _wxz #-}
+
+_wyx f = _xyzw $ \(V4 a b c d) -> f (V3 d b a) <&> \(V3 d' b' a') -> V4 a' b' c d'
+{-# INLINE _wyx #-}
+
+_wyz f = _xyzw $ \(V4 a b c d) -> f (V3 d b c) <&> \(V3 d' b' c') -> V4 a b' c' d'
+{-# INLINE _wyz #-}
+
+_wzx f = _xyzw $ \(V4 a b c d) -> f (V3 d c a) <&> \(V3 d' c' a') -> V4 a' b c' d'
+{-# INLINE _wzx #-}
+
+_wzy f = _xyzw $ \(V4 a b c d) -> f (V3 d c b) <&> \(V3 d' c' b') -> V4 a b' c' d'
+{-# INLINE _wzy #-}
+
+_xywz, _xzyw, _xzwy, _xwyz, _xwzy, _yxzw , _yxwz, _yzxw, _yzwx, _ywxz
+  , _ywzx, _zxyw, _zxwy, _zyxw, _zywx, _zwxy, _zwyx, _wxyz, _wxzy, _wyxz
+  , _wyzx, _wzxy, _wzyx :: R4 t => Lens' (t a) (V4 a)
+_xywz f = _xyzw $ \(V4 a b c d) -> f (V4 a b d c) <&> \(V4 a' b' d' c') -> V4 a' b' c' d'
+{-# INLINE _xywz #-}
+
+_xzyw f = _xyzw $ \(V4 a b c d) -> f (V4 a c b d) <&> \(V4 a' c' b' d') -> V4 a' b' c' d'
+{-# INLINE _xzyw #-}
+
+_xzwy f = _xyzw $ \(V4 a b c d) -> f (V4 a c d b) <&> \(V4 a' c' d' b') -> V4 a' b' c' d'
+{-# INLINE _xzwy #-}
+
+_xwyz f = _xyzw $ \(V4 a b c d) -> f (V4 a d b c) <&> \(V4 a' d' b' c') -> V4 a' b' c' d'
+{-# INLINE _xwyz #-}
+
+_xwzy f = _xyzw $ \(V4 a b c d) -> f (V4 a d c b) <&> \(V4 a' d' c' b') -> V4 a' b' c' d'
+{-# INLINE _xwzy #-}
+
+_yxzw f = _xyzw $ \(V4 a b c d) -> f (V4 b a c d) <&> \(V4 b' a' c' d') -> V4 a' b' c' d'
+{-# INLINE _yxzw #-}
+
+_yxwz f = _xyzw $ \(V4 a b c d) -> f (V4 b a d c) <&> \(V4 b' a' d' c') -> V4 a' b' c' d'
+{-# INLINE _yxwz #-}
+
+_yzxw f = _xyzw $ \(V4 a b c d) -> f (V4 b c a d) <&> \(V4 b' c' a' d') -> V4 a' b' c' d'
+{-# INLINE _yzxw #-}
+
+_yzwx f = _xyzw $ \(V4 a b c d) -> f (V4 b c d a) <&> \(V4 b' c' d' a') -> V4 a' b' c' d'
+{-# INLINE _yzwx #-}
+
+_ywxz f = _xyzw $ \(V4 a b c d) -> f (V4 b d a c) <&> \(V4 b' d' a' c') -> V4 a' b' c' d'
+{-# INLINE _ywxz #-}
+
+_ywzx f = _xyzw $ \(V4 a b c d) -> f (V4 b d c a) <&> \(V4 b' d' c' a') -> V4 a' b' c' d'
+{-# INLINE _ywzx #-}
+
+_zxyw f = _xyzw $ \(V4 a b c d) -> f (V4 c a b d) <&> \(V4 c' a' b' d') -> V4 a' b' c' d'
+{-# INLINE _zxyw #-}
+
+_zxwy f = _xyzw $ \(V4 a b c d) -> f (V4 c a d b) <&> \(V4 c' a' d' b') -> V4 a' b' c' d'
+{-# INLINE _zxwy #-}
+
+_zyxw f = _xyzw $ \(V4 a b c d) -> f (V4 c b a d) <&> \(V4 c' b' a' d') -> V4 a' b' c' d'
+{-# INLINE _zyxw #-}
+
+_zywx f = _xyzw $ \(V4 a b c d) -> f (V4 c b d a) <&> \(V4 c' b' d' a') -> V4 a' b' c' d'
+{-# INLINE _zywx #-}
+
+_zwxy f = _xyzw $ \(V4 a b c d) -> f (V4 c d a b) <&> \(V4 c' d' a' b') -> V4 a' b' c' d'
+{-# INLINE _zwxy #-}
+
+_zwyx f = _xyzw $ \(V4 a b c d) -> f (V4 c d b a) <&> \(V4 c' d' b' a') -> V4 a' b' c' d'
+{-# INLINE _zwyx #-}
+
+_wxyz f = _xyzw $ \(V4 a b c d) -> f (V4 d a b c) <&> \(V4 d' a' b' c') -> V4 a' b' c' d'
+{-# INLINE _wxyz #-}
+
+_wxzy f = _xyzw $ \(V4 a b c d) -> f (V4 d a c b) <&> \(V4 d' a' c' b') -> V4 a' b' c' d'
+{-# INLINE _wxzy #-}
+
+_wyxz f = _xyzw $ \(V4 a b c d) -> f (V4 d b a c) <&> \(V4 d' b' a' c') -> V4 a' b' c' d'
+{-# INLINE _wyxz #-}
+
+_wyzx f = _xyzw $ \(V4 a b c d) -> f (V4 d b c a) <&> \(V4 d' b' c' a') -> V4 a' b' c' d'
+{-# INLINE _wyzx #-}
+
+_wzxy f = _xyzw $ \(V4 a b c d) -> f (V4 d c a b) <&> \(V4 d' c' a' b') -> V4 a' b' c' d'
+{-# INLINE _wzxy #-}
+
+_wzyx f = _xyzw $ \(V4 a b c d) -> f (V4 d c b a) <&> \(V4 d' c' b' a') -> V4 a' b' c' d'
+{-# INLINE _wzyx #-}
+
+ew :: R4 t => E t
+ew = E _w
+
+instance R1 V4 where
   _x f (V4 a b c d) = (\a' -> V4 a' b c d) <$> f a
   {-# INLINE _x #-}
+
+instance R2 V4 where
   _y f (V4 a b c d) = (\b' -> V4 a b' c d) <$> f b
   {-# INLINE _y #-}
   _xy f (V4 a b c d) = (\(V2 a' b') -> V4 a' b' c d) <$> f (V2 a b)
@@ -163,10 +449,6 @@
   _xyzw = id
   {-# INLINE _xyzw #-}
 
-instance Core V4 where
-  core f = V4 (f _x) (f _y) (f _z) (f _w)
-  {-# INLINE core #-}
-
 instance Storable a => Storable (V4 a) where
   sizeOf _ = 4 * sizeOf (undefined::a)
   {-# INLINE sizeOf #-}
@@ -183,16 +465,27 @@
     where ptr' = castPtr ptr
   {-# INLINE peek #-}
 
--- | Convert a 3-dimensional affine vector into a 4-dimensional homogeneous vector.
+-- | Convert a 3-dimensional affine vector into a 4-dimensional homogeneous vector,
+-- i.e. sets the @w@ coordinate to 0.
 vector :: Num a => V3 a -> V4 a
 vector (V3 a b c) = V4 a b c 0
 {-# INLINE vector #-}
 
--- | Convert a 3-dimensional affine point into a 4-dimensional homogeneous vector.
+-- | Convert a 3-dimensional affine point into a 4-dimensional homogeneous vector,
+-- i.e. sets the @w@ coordinate to 1.
 point :: Num a => V3 a -> V4 a
 point (V3 a b c) = V4 a b c 1
 {-# INLINE point #-}
 
+-- | Convert 4-dimensional projective coordinates to a 3-dimensional
+-- point. This operation may be denoted, @euclidean [x:y:z:w] = (x\/w,
+-- y\/w, z\/w)@ where the projective, homogenous, coordinate
+-- @[x:y:z:w]@ is one of many associated with a single point @(x\/w,
+-- y\/w, z\/w)@.
+normalizePoint :: Fractional a => V4 a -> V3 a
+normalizePoint (V4 a b c w) = (1/w) *^ V3 a b c
+{-# INLINE normalizePoint #-}
+
 instance Epsilon a => Epsilon (V4 a) where
   nearZero = nearZero . quadrance
   {-# INLINE nearZero #-}
@@ -219,3 +512,147 @@
     inRange (l1,u1) i1 && inRange (l2,u2) i2 &&
     inRange (l3,u3) i3 && inRange (l4,u4) i4
   {-# INLINE inRange #-}
+
+instance Representable V4 where
+  type Rep V4 = E V4
+  tabulate f = V4 (f ex) (f ey) (f ez) (f ew)
+  {-# INLINE tabulate #-}
+  index xs (E l) = view l xs
+  {-# INLINE index #-}
+
+instance WithIndex.FunctorWithIndex (E V4) V4 where
+  imap f (V4 a b c d) = V4 (f ex a) (f ey b) (f ez c) (f ew d)
+  {-# INLINE imap #-}
+
+instance WithIndex.FoldableWithIndex (E V4) V4 where
+  ifoldMap f (V4 a b c d) = f ex a `mappend` f ey b `mappend` f ez c `mappend` f ew d
+  {-# INLINE ifoldMap #-}
+
+instance WithIndex.TraversableWithIndex (E V4) V4 where
+  itraverse f (V4 a b c d) = V4 <$> f ex a <*> f ey b <*> f ez c <*> f ew d
+  {-# INLINE itraverse #-}
+
+#if !MIN_VERSION_lens(5,0,0)
+instance Lens.FunctorWithIndex     (E V4) V4 where imap      = WithIndex.imap
+instance Lens.FoldableWithIndex    (E V4) V4 where ifoldMap  = WithIndex.ifoldMap
+instance Lens.TraversableWithIndex (E V4) V4 where itraverse = WithIndex.itraverse
+#endif
+
+type instance Index (V4 a) = E V4
+type instance IxValue (V4 a) = a
+
+instance Ixed (V4 a) where
+  ix i = el i
+
+instance Each (V4 a) (V4 b) a b where
+  each = traverse
+
+data instance U.Vector    (V4 a) =  V_V4 {-# UNPACK #-} !Int !(U.Vector    a)
+data instance U.MVector s (V4 a) = MV_V4 {-# UNPACK #-} !Int !(U.MVector s a)
+instance U.Unbox a => U.Unbox (V4 a)
+
+instance U.Unbox a => M.MVector U.MVector (V4 a) where
+  basicLength (MV_V4 n _) = n
+  basicUnsafeSlice m n (MV_V4 _ v) = MV_V4 n (M.basicUnsafeSlice (4*m) (4*n) v)
+  basicOverlaps (MV_V4 _ v) (MV_V4 _ u) = M.basicOverlaps v u
+  basicUnsafeNew n = liftM (MV_V4 n) (M.basicUnsafeNew (4*n))
+  basicUnsafeRead (MV_V4 _ v) i =
+    do let o = 4*i
+       x <- M.basicUnsafeRead v o
+       y <- M.basicUnsafeRead v (o+1)
+       z <- M.basicUnsafeRead v (o+2)
+       w <- M.basicUnsafeRead v (o+3)
+       return (V4 x y z w)
+  basicUnsafeWrite (MV_V4 _ v) i (V4 x y z w) =
+    do let o = 4*i
+       M.basicUnsafeWrite v o     x
+       M.basicUnsafeWrite v (o+1) y
+       M.basicUnsafeWrite v (o+2) z
+       M.basicUnsafeWrite v (o+3) w
+  basicInitialize (MV_V4 _ v) = M.basicInitialize v
+
+instance U.Unbox a => G.Vector U.Vector (V4 a) where
+  basicUnsafeFreeze (MV_V4 n v) = liftM ( V_V4 n) (G.basicUnsafeFreeze v)
+  basicUnsafeThaw   ( V_V4 n v) = liftM (MV_V4 n) (G.basicUnsafeThaw   v)
+  basicLength       ( V_V4 n _) = n
+  basicUnsafeSlice m n (V_V4 _ v) = V_V4 n (G.basicUnsafeSlice (4*m) (4*n) v)
+  basicUnsafeIndexM (V_V4 _ v) i =
+    do let o = 4*i
+       x <- G.basicUnsafeIndexM v o
+       y <- G.basicUnsafeIndexM v (o+1)
+       z <- G.basicUnsafeIndexM v (o+2)
+       w <- G.basicUnsafeIndexM v (o+3)
+       return (V4 x y z w)
+
+instance MonadZip V4 where
+  mzipWith = liftA2
+
+instance MonadFix V4 where
+  mfix f = V4 (let V4 a _ _ _ = f a in a)
+              (let V4 _ a _ _ = f a in a)
+              (let V4 _ _ a _ = f a in a)
+              (let V4 _ _ _ a = f a in a)
+
+instance Bounded a => Bounded (V4 a) where
+  minBound = pure minBound
+  {-# INLINE minBound #-}
+  maxBound = pure maxBound
+  {-# INLINE maxBound #-}
+
+instance NFData a => NFData (V4 a) where
+  rnf (V4 a b c d) = rnf a `seq` rnf b `seq` rnf c `seq` rnf d
+
+instance Serial1 V4 where
+  serializeWith = traverse_
+  deserializeWith k = V4 <$> k <*> k <*> k <*> k
+
+instance Serial a => Serial (V4 a) where
+  serialize = serializeWith serialize
+  deserialize = deserializeWith deserialize
+
+instance Binary a => Binary (V4 a) where
+  put = serializeWith Binary.put
+  get = deserializeWith Binary.get
+
+instance Serialize a => Serialize (V4 a) where
+  put = serializeWith Cereal.put
+  get = deserializeWith Cereal.get
+
+instance Eq1 V4 where
+  liftEq k (V4 a b c d) (V4 e f g h) = k a e && k b f && k c g && k d h
+instance Ord1 V4 where
+  liftCompare k (V4 a b c d) (V4 e f g h) = k a e `mappend` k b f `mappend` k c g `mappend` k d h
+instance Read1 V4 where
+  liftReadsPrec k _ z = readParen (z > 10) $ \r ->
+     [ (V4 a b c d, r5)
+     | ("V4",r1) <- lex r
+     , (a,r2) <- k 11 r1
+     , (b,r3) <- k 11 r2
+     , (c,r4) <- k 11 r3
+     , (d,r5) <- k 11 r4
+     ]
+instance Show1 V4 where
+  liftShowsPrec f _ z (V4 a b c d) = showParen (z > 10) $
+     showString "V4 " . f 11 a . showChar ' ' . f 11 b . showChar ' ' . f 11 c . showChar ' ' . f 11 d
+
+instance Field1 (V4 a) (V4 a) a a where
+  _1 f (V4 x y z w) = f x <&> \x' -> V4 x' y z w
+
+instance Field2 (V4 a) (V4 a) a a where
+  _2 f (V4 x y z w) = f y <&> \y' -> V4 x y' z w
+
+instance Field3 (V4 a) (V4 a) a a where
+  _3 f (V4 x y z w) = f z <&> \z' -> V4 x y z' w
+
+instance Field4 (V4 a) (V4 a) a a where
+  _4 f (V4 x y z w) = f w <&> \w' -> V4 x y z w'
+
+instance Semigroup a => Semigroup (V4 a) where
+ (<>) = liftA2 (<>)
+
+instance Monoid a => Monoid (V4 a) where
+  mempty = pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend = liftA2 mappend
+#endif
+
diff --git a/src/Linear/Vector.hs b/src/Linear/Vector.hs
--- a/src/Linear/Vector.hs
+++ b/src/Linear/Vector.hs
@@ -1,9 +1,14 @@
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE DefaultSignatures #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Linear.Vector
--- Copyright   :  (C) 2012 Edward Kmett
+-- Copyright   :  (C) 2012-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
 -- Stability   :  provisional
@@ -13,41 +18,103 @@
 -----------------------------------------------------------------------------
 module Linear.Vector
   ( Additive(..)
+  , E(..)
   , negated
   , (^*)
   , (*^)
   , (^/)
+  , sumV
   , basis
   , basisFor
+  , scaled
+  , outer
+  , unit
   ) where
 
 import Control.Applicative
+import Control.Lens
 import Data.Complex
-import Data.Foldable (foldMap)
-import Data.Functor.Bind
-import Data.Functor.Identity
+import Data.Foldable as Foldable (forM_, foldl')
+import Data.Functor.Compose
+import Data.Functor.Product
 import Data.HashMap.Lazy as HashMap
 import Data.Hashable
 import Data.IntMap as IntMap
 import Data.Map as Map
-import Data.Monoid (Sum(..))
-import Data.Traversable (Traversable, mapAccumL)
+import qualified Data.Vector as Vector
+import Data.Vector (Vector)
+import qualified Data.Vector.Mutable as Mutable
+import GHC.Generics
 import Linear.Instances ()
 
 -- $setup
--- >>> import Control.Lens
 -- >>> import Linear.V2
 
+-- | Basis element
+newtype E t = E { el :: forall x. Lens' (t x) x }
+
 infixl 6 ^+^, ^-^
 infixl 7 ^*, *^, ^/
 
+class GAdditive f where
+  gzero :: Num a => f a
+  gliftU2 :: (a -> a -> a) -> f a -> f a -> f a
+  gliftI2 :: (a -> b -> c) -> f a -> f b -> f c
+
+instance GAdditive U1 where
+  gzero = U1
+  {-# INLINE gzero #-}
+  gliftU2 _ U1 U1 = U1
+  {-# INLINE gliftU2 #-}
+  gliftI2 _ U1 U1 = U1
+  {-# INLINE gliftI2 #-}
+
+instance (GAdditive f, GAdditive g) => GAdditive (f :*: g) where
+  gzero = gzero :*: gzero
+  {-# INLINE gzero #-}
+  gliftU2 f (a :*: b) (c :*: d) = gliftU2 f a c :*: gliftU2 f b d
+  {-# INLINE gliftU2 #-}
+  gliftI2 f (a :*: b) (c :*: d) = gliftI2 f a c :*: gliftI2 f b d
+  {-# INLINE gliftI2 #-}
+
+instance (Additive f, GAdditive g) => GAdditive (f :.: g) where
+  gzero = Comp1 $ gzero <$ (zero :: f Int)
+  {-# INLINE gzero #-}
+  gliftU2 f (Comp1 a) (Comp1 b) = Comp1 $ liftU2 (gliftU2 f) a b
+  {-# INLINE gliftU2 #-}
+  gliftI2 f (Comp1 a) (Comp1 b) = Comp1 $ liftI2 (gliftI2 f) a b
+  {-# INLINE gliftI2 #-}
+
+instance Additive f => GAdditive (Rec1 f) where
+  gzero = Rec1 zero
+  {-# INLINE gzero #-}
+  gliftU2 f (Rec1 g) (Rec1 h) = Rec1 (liftU2 f g h)
+  {-# INLINE gliftU2 #-}
+  gliftI2 f (Rec1 g) (Rec1 h) = Rec1 (liftI2 f g h)
+  {-# INLINE gliftI2 #-}
+
+instance GAdditive f => GAdditive (M1 i c f) where
+  gzero = M1 gzero
+  {-# INLINE gzero #-}
+  gliftU2 f (M1 g) (M1 h) = M1 (gliftU2 f g h)
+  {-# INLINE gliftU2 #-}
+  gliftI2 f (M1 g) (M1 h) = M1 (gliftI2 f g h)
+  {-# INLINE gliftI2 #-}
+
+instance GAdditive Par1 where
+  gzero = Par1 0
+  gliftU2 f (Par1 a) (Par1 b) = Par1 (f a b)
+  {-# INLINE gliftU2 #-}
+  gliftI2 f (Par1 a) (Par1 b) = Par1 (f a b)
+  {-# INLINE gliftI2 #-}
+
 -- | A vector is an additive group with additional structure.
-class Bind f => Additive f where
+class Functor f => Additive f where
   -- | The zero vector
   zero :: Num a => f a
 #ifndef HLINT
-  default zero :: (Applicative f, Num a) => f a
-  zero = pure 0
+  default zero :: (GAdditive (Rep1 f), Generic1 f, Num a) => f a
+  zero = to1 gzero
 #endif
 
   -- | Compute the sum of two vectors
@@ -55,48 +122,162 @@
   -- >>> V2 1 2 ^+^ V2 3 4
   -- V2 4 6
   (^+^) :: Num a => f a -> f a -> f a
-#ifndef HLINT
-  default (^+^) :: (Applicative f, Num a) => f a -> f a -> f a
-  (^+^) = liftA2 (+)
+  (^+^) = liftU2 (+)
   {-# INLINE (^+^) #-}
-#endif
 
   -- | Compute the difference between two vectors
   --
-  -- >>> V2 4 5 - V2 3 1
+  -- >>> V2 4 5 ^-^ V2 3 1
   -- V2 1 4
   (^-^) :: Num a => f a -> f a -> f a
-#ifndef HLINT
-  default (^-^) :: (Applicative f, Num a) => f a -> f a -> f a
-  (^-^) = liftA2 (-)
-  {-# INLINE (^-^) #-}
-#endif
+  x ^-^ y = x ^+^ negated y
 
   -- | Linearly interpolate between two vectors.
+  --
+  -- /Since linear version 1.23, interpolation direction has been reversed; now/
+  --
+  -- > lerp 0 a b == a
+  -- > lerp 1 a b == b
   lerp :: Num a => a -> f a -> f a -> f a
-  lerp alpha u v = alpha *^ u ^+^ (1 - alpha) *^ v
+  lerp alpha u v = (1 - alpha) *^ u ^+^ alpha *^ v
   {-# INLINE lerp #-}
 
+  -- | Apply a function to merge the 'non-zero' components of two vectors, unioning the rest of the values.
+  --
+  -- * For a dense vector this is equivalent to 'liftA2'.
+  --
+  -- * For a sparse vector this is equivalent to 'unionWith'.
+  liftU2 :: (a -> a -> a) -> f a -> f a -> f a
+#ifndef HLINT
+  default liftU2 :: Applicative f => (a -> a -> a) -> f a -> f a -> f a
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+#endif
+
+  -- | Apply a function to the components of two vectors.
+  --
+  -- * For a dense vector this is equivalent to 'liftA2'.
+  --
+  -- * For a sparse vector this is equivalent to 'intersectionWith'.
+  liftI2 :: (a -> b -> c) -> f a -> f b -> f c
+#ifndef HLINT
+  default liftI2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
+#endif
+
+instance (Additive f, Additive g) => Additive (Product f g) where
+  zero = Pair zero zero
+  liftU2 f (Pair a b) (Pair c d) = Pair (liftU2 f a c) (liftU2 f b d)
+  liftI2 f (Pair a b) (Pair c d) = Pair (liftI2 f a c) (liftI2 f b d)
+  Pair a b ^+^ Pair c d = Pair (a ^+^ c) (b ^+^ d)
+  Pair a b ^-^ Pair c d = Pair (a ^-^ c) (b ^-^ d)
+  lerp alpha (Pair a b) (Pair c d) = Pair (lerp alpha a c) (lerp alpha b d)
+
+instance (Additive f, Additive g) => Additive (Compose f g) where
+  zero = Compose $ zero <$ (zero :: f Int)
+  {-# INLINE zero #-}
+  Compose a ^+^ Compose b = Compose $ liftU2 (^+^) a b
+  {-# INLINE (^+^) #-}
+  Compose a ^-^ Compose b = Compose $ liftU2 (^-^) a b
+  {-# INLINE (^-^) #-}
+  liftU2 f (Compose a) (Compose b) = Compose $ liftU2 (liftU2 f) a b
+  {-# INLINE liftU2 #-}
+  liftI2 f (Compose a) (Compose b) = Compose $ liftI2 (liftI2 f) a b
+  {-# INLINE liftI2 #-}
+
+instance Additive ZipList where
+  zero = ZipList []
+  {-# INLINE zero #-}
+  liftU2 f (ZipList xs) (ZipList ys) = ZipList (liftU2 f xs ys)
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
+
+instance Additive Vector where
+  zero = mempty
+  {-# INLINE zero #-}
+  liftU2 f u v = case compare lu lv of
+    LT | lu == 0   -> v
+       | otherwise -> Vector.modify (\ w -> Foldable.forM_ [0..lu-1] $ \i -> Mutable.unsafeWrite w i $ f (Vector.unsafeIndex u i) (Vector.unsafeIndex v i)) v
+    EQ -> Vector.zipWith f u v
+    GT | lv == 0   -> u
+       | otherwise -> Vector.modify (\ w -> Foldable.forM_ [0..lv-1] $ \i -> Mutable.unsafeWrite w i $ f (Vector.unsafeIndex u i) (Vector.unsafeIndex v i)) u
+    where
+      lu = Vector.length u
+      lv = Vector.length v
+  {-# INLINE liftU2 #-}
+  liftI2 = Vector.zipWith
+  {-# INLINE liftI2 #-}
+
+instance Additive Maybe where
+  zero = Nothing
+  {-# INLINE zero #-}
+  liftU2 f (Just a) (Just b) = Just (f a b)
+  liftU2 _ Nothing ys = ys
+  liftU2 _ xs Nothing = xs
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
+
+instance Additive [] where
+  zero = []
+  {-# INLINE zero #-}
+  liftU2 f = go where
+    go (x:xs) (y:ys) = f x y : go xs ys
+    go [] ys = ys
+    go xs [] = xs
+  {-# INLINE liftU2 #-}
+  liftI2 = Prelude.zipWith
+  {-# INLINE liftI2 #-}
+
 instance Additive IntMap where
   zero = IntMap.empty
-  (^+^) = IntMap.unionWith (+)
-  xs ^-^ ys = IntMap.unionWith (+) xs (negated ys)
+  {-# INLINE zero #-}
+  liftU2 = IntMap.unionWith
+  {-# INLINE liftU2 #-}
+  liftI2 = IntMap.intersectionWith
+  {-# INLINE liftI2 #-}
 
 instance Ord k => Additive (Map k) where
   zero = Map.empty
-  (^+^) = Map.unionWith (+)
-  xs ^-^ ys = Map.unionWith (+) xs (negated ys)
+  {-# INLINE zero #-}
+  liftU2 = Map.unionWith
+  {-# INLINE liftU2 #-}
+  liftI2 = Map.intersectionWith
+  {-# INLINE liftI2 #-}
 
 instance (Eq k, Hashable k) => Additive (HashMap k) where
   zero = HashMap.empty
-  (^+^) = HashMap.unionWith (+)
-  xs ^-^ ys = HashMap.unionWith (+) xs (negated ys)
+  {-# INLINE zero #-}
+  liftU2 = HashMap.unionWith
+  {-# INLINE liftU2 #-}
+  liftI2 = HashMap.intersectionWith
+  {-# INLINE liftI2 #-}
 
-instance Additive ((->) b)
+instance Additive ((->) b) where
+  zero   = const 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
-instance Additive Complex
+instance Additive Complex where
+  zero = 0 :+ 0
+  {-# INLINE zero #-}
+  liftU2 f (a :+ b) (c :+ d) = f a c :+ f b d
+  {-# INLINE liftU2 #-}
+  liftI2 f (a :+ b) (c :+ d) = f a c :+ f b d
+  {-# INLINE liftI2 #-}
 
-instance Additive Identity
+instance Additive Identity where
+  zero = Identity 0
+  {-# INLINE zero #-}
+  liftU2 = liftA2
+  {-# INLINE liftU2 #-}
+  liftI2 = liftA2
+  {-# INLINE liftI2 #-}
 
 -- | Compute the negation of a vector
 --
@@ -106,6 +287,14 @@
 negated = fmap negate
 {-# INLINE negated #-}
 
+-- | Sum over multiple vectors
+--
+-- >>> sumV [V2 1 1, V2 3 4]
+-- V2 4 5
+sumV :: (Foldable f, Additive v, Num a) => f (v a) -> v a
+sumV = Foldable.foldl' (^+^) zero
+{-# INLINE sumV #-}
+
 -- | Compute the left scalar product
 --
 -- >>> 2 *^ V2 3 4
@@ -127,23 +316,39 @@
 f ^/ a = fmap (/a) f
 {-# INLINE (^/) #-}
 
--- @setElement i x v@ sets the @i@'th element of @v@ to @x@.
-setElement :: Traversable t => Int -> a -> t a -> t a
-setElement i x = snd . mapAccumL aux 0
-  where aux j y = let j' = j + 1
-                      y' = if i == j then x else y
-                  in j' `seq` (j', y')
-
 -- | Produce a default basis for a vector space. If the dimensionality
 -- of the vector space is not statically known, see 'basisFor'.
-basis :: (Applicative t, Traversable t, Num a) => [t a]
-basis = [ setElement k 1 z | k <- [0..n - 1] ]
-  where z = pure 0
-        n = getSum $ foldMap (const (Sum 1)) z
+basis :: (Additive t, Traversable t, Num a) => [t a]
+basis = basisFor (zero :: Additive v => v Int)
 
 -- | Produce a default basis for a vector space from which the
 -- argument is drawn.
-basisFor :: (Traversable t, Enum a, Num a) => t a -> [t a]
-basisFor v = [ setElement k 1 z | k <- [0..n-1] ]
-  where z = 0 <$ v
-        n = getSum $ foldMap (const (Sum 1)) v
+basisFor :: (Traversable t, Num a) => t b -> [t a]
+basisFor = \t ->
+   ifoldMapOf traversed ?? t $ \i _ ->
+     return                  $
+       iover  traversed ?? t $ \j _ ->
+         if i == j then 1 else 0
+{-# INLINABLE basisFor #-}
+
+-- | Produce a diagonal (scale) matrix from a vector.
+--
+-- >>> scaled (V2 2 3)
+-- V2 (V2 2 0) (V2 0 3)
+scaled :: (Traversable t, Num a) => t a -> t (t a)
+scaled = \t -> iter t (\i x -> iter t (\j _ -> if i == j then x else 0))
+  where
+  iter :: Traversable t => t a -> (Int -> a -> b) -> t b
+  iter x f = iover traversed f x
+{-# INLINE scaled #-}
+
+-- | Create a unit vector.
+--
+-- >>> unit _x :: V2 Int
+-- V2 1 0
+unit :: (Additive t, Num a) => ASetter' (t a) a -> t a
+unit l = set' l 1 zero
+
+-- | Outer (tensor) product of two vectors
+outer :: (Functor f, Functor g, Num a) => f a -> g a -> f (g a)
+outer a b = fmap (\x->fmap (*x) b) a
diff --git a/tests/Prop/Quaternion.hs b/tests/Prop/Quaternion.hs
new file mode 100644
--- /dev/null
+++ b/tests/Prop/Quaternion.hs
@@ -0,0 +1,28 @@
+{-# OPTIONS_GHC -Wno-orphans #-}
+module Prop.Quaternion (tests) where
+
+import Linear.Quaternion (Quaternion(..))
+import Linear.Epsilon (nearZero)
+import Linear.Vector (lerp)
+import Test.QuickCheck (Arbitrary(..))
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.QuickCheck (testProperty)
+
+import Prop.V3 ()
+
+instance Arbitrary a => Arbitrary (Quaternion a) where
+  arbitrary = Quaternion <$> arbitrary <*> arbitrary
+
+prop_lerp0 :: Quaternion Double -> Quaternion Double -> Bool
+prop_lerp0 a b = nearZero (lerp 0 a b - a)
+
+prop_lerp1 :: Quaternion Double -> Quaternion Double -> Bool
+prop_lerp1 a b = nearZero (lerp 1 a b - b)
+
+tests :: [TestTree]
+tests =
+  [ testGroup "lerp"
+    [ testProperty "lerp 0 a b == a" prop_lerp0
+    , testProperty "lerp 1 a b == b" prop_lerp1
+    ]
+  ]
diff --git a/tests/Prop/V3.hs b/tests/Prop/V3.hs
new file mode 100644
--- /dev/null
+++ b/tests/Prop/V3.hs
@@ -0,0 +1,8 @@
+{-# OPTIONS_GHC -Wno-orphans #-}
+module Prop.V3 () where
+
+import Linear.V3 (V3(..))
+import Test.QuickCheck (Arbitrary(..))
+
+instance Arbitrary a => Arbitrary (V3 a) where
+  arbitrary = V3 <$> arbitrary <*> arbitrary <*> arbitrary
diff --git a/tests/Test.hs b/tests/Test.hs
new file mode 100644
--- /dev/null
+++ b/tests/Test.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE CPP #-}
+module Main (main) where
+
+import Test.Tasty (defaultMain, testGroup, TestTree)
+
+import qualified Prop.Quaternion
+import qualified Unit.Binary
+import qualified Unit.Plucker
+import qualified Unit.V
+
+tests :: [TestTree]
+tests =
+  [ testGroup "Property tests"
+    [ testGroup "Quaternion" Prop.Quaternion.tests
+    ]
+  , testGroup "Unit tests"
+    [ testGroup "Binary" Unit.Binary.tests
+    , testGroup "Plucker" Unit.Plucker.tests
+    , testGroup "V" Unit.V.tests
+    ]
+  ]
+
+main :: IO ()
+main = defaultMain $ testGroup "linear" tests
diff --git a/tests/Unit/Binary.hs b/tests/Unit/Binary.hs
new file mode 100644
--- /dev/null
+++ b/tests/Unit/Binary.hs
@@ -0,0 +1,20 @@
+module Unit.Binary (tests) where
+
+import Data.Binary.Put
+import Data.Binary.Get
+import Linear
+import qualified Data.ByteString.Lazy as BS
+import Test.Tasty (TestTree)
+import Test.Tasty.HUnit ((@?=), testCase)
+
+originalVecs :: (V3 Float, V2 Char)
+originalVecs = (V3 1 2 3, V2 'a' 'b')
+
+bytes :: BS.ByteString
+bytes = runPut $ do putLinear $ fst originalVecs
+                    putLinear $ snd originalVecs
+
+tests :: [TestTree]
+tests = [ testCase "Serialized length" $ BS.length bytes @?= 3*13+2
+        , testCase "Deserialization" $ deserialized @?= originalVecs ]
+  where deserialized = runGet ((,) <$> getLinear <*> getLinear) bytes
diff --git a/tests/Unit/Plucker.hs b/tests/Unit/Plucker.hs
new file mode 100644
--- /dev/null
+++ b/tests/Unit/Plucker.hs
@@ -0,0 +1,36 @@
+module Unit.Plucker (tests) where
+import Linear
+import Linear.Plucker
+import Linear.Plucker.Coincides
+import Test.Tasty (TestTree)
+import Test.Tasty.HUnit ((@?=), testCase)
+
+ln2,ln3,ln4,ln5,ln6,ln7,ln8,ln9 :: Plucker Float
+ln2 = plucker3D (V3 1 3 0) (V3 1 3 (-2))    -- starting line
+ln3 = plucker3D (V3 2 3 0) (V3 2 3 (-2))    -- parallel
+ln4 = plucker3D (V3 2 4 0) (V3 1 4 (-2))    -- ccw
+ln5 = plucker3D (V3 (-2) 4 0) (V3 2 4 (-2)) -- cw
+ln6 = plucker3D (V3 2 3 0) (V3 1 3 (-2))    -- intersect
+ln7 = plucker3D (V3 1 3 0) (V3 1 3 2)       -- reversed
+ln8 = plucker3D (V3 0 4 4) (V3 0 (-4) (-4)) -- through origin
+ln9 = Plucker 1 2 3 4 5 6                   -- not a 3D line
+
+tests :: [TestTree]
+tests = [ testCase "parallel" $ parallel ln2 ln3 @?= True
+        , testCase "CCW" $ passes ln2 ln4 @?= Counterclockwise
+        , testCase "CW" $ passes ln2 ln5 @?= Clockwise
+        , testCase "intersect1" $ intersects ln2 ln6 @?= True
+        , testCase "intersect2" $ intersects ln2 ln3 @?= False
+        , testCase "line equality 1" $ Line ln2 == Line ln2 @?= True
+        , testCase "line equality 2" $ Line ln2 == Line ln7 @?= True
+        , testCase "line equality 3" $ Line ln2 == Ray ln7 @?= True
+        , testCase "line equality 4" $ Ray ln2 == Line ln7 @?= True
+        , testCase "ray equality 1" $ Ray ln2 == Ray ln7 @?= False
+        , testCase "ray equality 2" $ Ray ln2 == Ray (3 *^ ln2) @?= True
+        , testCase "ray equality 3" $ Ray ln2 == Ray (negate ln7) @?= True
+        , testCase "quadrance" $ nearZero (quadranceToOrigin ln2 - 10) @?= True
+        , testCase "closest 1" $
+            nearZero (qd (V3 1 3 0) $ closestToOrigin ln2) @?= True
+        , testCase "closest 2" $ nearZero (qd 0 $ closestToOrigin ln8) @?= True
+        , testCase "isLine 1" $ isLine ln2 @?= True
+        , testCase "isLine 2" $ isLine ln9 @?= False ]
diff --git a/tests/Unit/V.hs b/tests/Unit/V.hs
new file mode 100644
--- /dev/null
+++ b/tests/Unit/V.hs
@@ -0,0 +1,14 @@
+{-# LANGUAGE DataKinds #-}
+module Unit.V (tests) where
+
+import Control.DeepSeq (rnf)
+import qualified Data.Vector.Unboxed as U (fromList)
+import Linear.V (V)
+import Test.Tasty (TestTree)
+import Test.Tasty.HUnit ((@?=), testCase)
+
+v10 :: V 10 Int
+v10 = return 5
+
+tests :: [TestTree]
+tests = [ testCase "GH124" $ rnf (U.fromList [v10]) @?= () ]
diff --git a/tests/doctests.hs b/tests/doctests.hs
--- a/tests/doctests.hs
+++ b/tests/doctests.hs
@@ -1,30 +1,19 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Main (doctests)
+-- Copyright   :  (C) 2012-14 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- This module exists to add dependencies
+-----------------------------------------------------------------------------
 module Main where
 
-import Build_doctests (deps)
-import Control.Applicative
-import Control.Monad
-import Data.List
-import System.Directory
-import System.FilePath
-import Test.DocTest
-
 main :: IO ()
-main = getSources >>= \sources -> doctest $
-    "-isrc"
-  : "-idist/build/autogen"
-  : "-optP-include"
-  : "-optPdist/build/autogen/cabal_macros.h"
-  : "-hide-all-packages"
-  : map ("-package="++) deps ++ sources
-
-getSources :: IO [FilePath]
-getSources = filter (isSuffixOf ".hs") <$> go "src"
-  where
-    go dir = do
-      (dirs, files) <- getFilesAndDirectories dir
-      (files ++) . concat <$> mapM go dirs
-
-getFilesAndDirectories :: FilePath -> IO ([FilePath], [FilePath])
-getFilesAndDirectories dir = do
-  c <- map (dir </>) . filter (`notElem` ["..", "."]) <$> getDirectoryContents dir
-  (,) <$> filterM doesDirectoryExist c <*> filterM doesFileExist c
+main = do
+    putStrLn "This test-suite exists only to add dependencies"
+    putStrLn "To run doctests: "
+    putStrLn "    cabal build all --enable-tests"
+    putStrLn "    cabal-docspec"
diff --git a/travis/cabal-apt-install b/travis/cabal-apt-install
deleted file mode 100644
--- a/travis/cabal-apt-install
+++ /dev/null
@@ -1,16 +0,0 @@
-#!/bin/sh
-set -eu
-
-sudo apt-get -q update
-sudo apt-get -q -y install dctrl-tools
-
-# Try installing some of the build-deps with apt-get for speed.
-eval "$(
-  printf '%s' "grep-aptavail -n -sPackage '(' -FFALSE -X FALSE ')'"
-  2>/dev/null cabal install "$@" --dry-run -v | \
-  sed -nre "s/^([^ ]+)-[0-9.]+ \(.*$/ -o '(' -FPackage -X libghc-\1-dev ')'/p" | \
-  xargs -d'\n'
-)" | sort -u | xargs -d'\n' sudo apt-get -q -y install -- libghc-quickcheck2-dev
-
-# Install whatever is still needed with cabal.
-cabal install "$@"
diff --git a/travis/config b/travis/config
deleted file mode 100644
--- a/travis/config
+++ /dev/null
@@ -1,16 +0,0 @@
--- This provides a custom ~/.cabal/config file for use when hackage is down that should work on unix
---
--- This is particularly useful for travis-ci to get it to stop complaining
--- about a broken build when everything is still correct on our end.
---
--- This uses Luite Stegeman's mirror of hackage provided by his 'hdiff' site instead
---
--- To enable this, uncomment the before_script in .travis.yml
-
-remote-repo: hdiff.luite.com:http://hdiff.luite.com/packages/archive
-remote-repo-cache: ~/.cabal/packages
-world-file: ~/.cabal/world
-build-summary: ~/.cabal/logs/build.log
-remote-build-reporting: anonymous
-install-dirs user
-install-dirs global
